ma thesis: an examination of some aspects of the astronomica of manilius

Title: An Examination of Some Aspects of the

Astronomica of Manilius

A thesis presented for the degree of Master of Arts in the

Department of Classics and Ancient History

University of Western Australia

Presented 1998

by Ian Carl Reide

Presented 1998

Table of Contents

Table of Contents..............................................................................i-vii

Acknowledgements...........................................................................viii

Preface.................................................................................................ix-x

1. Chapter One: An Examination of the Astronomica

1.1 Stoicism, Astrology, Astronomy and the

Meaning of the Astronomica ...................................................1

1.2 Summary of the Astronomica. of Manilius...............................4

1.2.1 Introduction

1.2.2 Book One

1.2.3 Book Two

1.2.4 Book Three

1.2.5 Book Four

1.2.6 Book Five

1.3 The Date of the Astronomica....................................................23

1.3.1 Introduction

1.3.2 Summary of Evidence and Arguments

1.3.3 The Question of Augustus’ Birth and Sign

1.3.4 The State of the Heavens

1.3.5 Rhodes, Tiberius, Libra and Book Four

1.3.6 Book Five

1.3.7 Conclusion

1.4 Sources of the Astronomica.......................................................38

1.4.1 Introduction

1.4.2 Aratus and his Influence on the Astronomica

1.4.2.1 Introduction

1.4.2.2 Summary of the Phaenomena

1.4.2.3 An Overview of the Two Works

1.4.2.4 An Examination of the Individual Constellations

of the Phaenomena and the Astronomica

1.4.2.5 An Examination of Religion in the Two Works

1.4.2.6 References in the Astronomica to the Phaenomena

1.4.2.7 Conclusion to Aratus

1.4.3 Manilius’ Stoic Sources

1.4.4 Manilius’ Astrological Sources

1.4.5 Manilius’ Astronomical Sources

1.4.6 Conclusion

Chapter Two: Manilius and His Intellectual Environment

2.1 A History of Astronomy & Astrology....................................59

2.1.1 Introduction

2.1.2 The Astronomy of the Greeks

2.1.3 The Fourth Century

2.1.4 The Hellenistic Period

2.1.5 The Astrology of the Greeks and Romans

2.2 The Beliefs and Personality of Manilius.................................70

2.2.1 Introduction

2.2.2 Personality

2.2.3 The Imperial System

2.2.4. Manilius as an Observer of the Heavens

2.2.5 Manilius and Mathematics

2.2.6 Manilius as an Astronomer

2.2.7 Manilius’ Stoicism

2.2.7.1 Stoicism in the Astronomica

2.2.7.2 Manilius’ Means of Argument

2.2.8 Conclusion to Manilius’ Beliefs and Personality

3. Chapter Three: Astronomy in the Astronomica

3.1 Introduction...............................................................................89

3.2 The Spherical Universe............................................................94

3.2.1 Introduction

3.2.2 The Overall Shape and Path of the Seven Planets

3.2.3 The Spherical Shape of the Earth

3.2.4 Suggestions of a Non–spherical Celestial Sphere

3.2.5 Conclusion

3.3 The Celestial Circles................................................................104

3.3.1 Introduction

3.3.2 Manilius’ Celestial Circles

3.3.3 The Zodiac

3.3.4 The Precession of the Equinoxes

3.3.5 The Location of the Colure Points

3.3.6 Conclusion

3.4 Constellations..........................................................................116

3.4.1 Introduction

3.4.2 The Constellation Catalogue of Manilius

3.4.3 Anomalies in Manilius’ Catalogue

3.4.4 Conclusion

3.5 Planets.......................................................................................122

3.5.1 Introduction

3.5.2 The Order of the Planets

3.5.3 Retrograde Planetary Motion

3.5.4 Conclusion

3.6 Stellar Magnitude....................................................................127

3.6.1 Introduction

3.6.2 Manilius’ Text

3.6.3 Constellations v. Stars v. Brightness

3.6.4 Hipparchus, Ptolemy and the Stellar Catalogue

3.6.5 Conclusion

4. Chapter Four:

The Colour of the Star Sirius in Antiquity ......................134

4.1 Introduction

4.2 Modern Discussion

4.3 Ancient Sources

4.3.1 Homer

4.3.2 Cicero

4.3.3 Horace

4.3.4 Seneca

4.3.5 Claudius Ptolemy

4.3.6 Manilius

4.4 Conclusion

4.4 Conclusion

5. Chapter Five: The Astrology of the Astronomica............148

5.1 Introduction

5.2 A Philosophical Basis for Astrology

5.3 Empirical Arguments for Astrology

5.4 The Worth of Manilius’ Astrological Procedures

6. Chapter Six: An Astronomical Examination of the

‘Horoscope’ Formulae of Book Three...........156

6.1 Introduction

6.2 Summary of the Horoscope Formulae

6.3 The ‘Two hour’ Rise Formula: 3.218–46 (No. 1)

6.4 Introduction to the Second Formula: 3.247–74 (No. 2)

6.5 First Explanation of Principal Formula: 3.275–300 (No. 3)

6.6 The Babylonian Basis of Manilius’ Formulae

6.7 Explanation of the Importance of Latitude

in Horoscope Calculation: 3.301–84 (No. 4)

6.8 The Principal Formula in a Version Accurate

for all Latitudes: 3.385–442 (No. 5)

6.9 A Description of the Change in the Duration of

Daylight over the Course of the Year: 3.443–482 (No.6)

6.10 The Second Version of the ‘Two hour’ Rise

Formula: 3.483–509 (No. 7)

6.11 Conclusion to the Horoscope Formulae


Tables

Table 1. Comparison of the Order of the

Constellations in the Phaenomena

and the Astronomica ............................................43

Table 2. List of Celestial Circles in the

Astronomica and Phaenomena...............................44

Table 3. Seasons Ascribed to Zodiacal

Constellations: 2.666–9......................................113

Table 4. Calculation of Day / Night Periods

over the 12 months June A.D. 14–May

A.D. 15 at the Latitude of Rome

as compared to System A & B.........................178

Diagrams

Diagram 1. Manilius’ Cosmology..........................................54

Appendices

Appendix A. Glossary of Astronomical Terms.................184

Appendix B. Order of constellations in Aratus’

Phaenomena and Manilius’ Astronomica..............................188

Bibliography and Reading List......................................................189

Ancient sources..................................................................................190

Secondary Sources.............................................................................196

Secondary Sources.............................................................................196

Acknowledgements

I would like to thank my supervisor, Dr. Jane Bellemore for her help,

assistance and support over the course of this thesis. I also wish to thank

the UWA Department of Classics and Ancient History for their support

over my lengthy, part-time enrolment. For their assistance in searching

for obscure texts and inter-library loans the staff of the University of

Western Australia Library deserve a special mention. Lastly, I would like

to thank two scholars whose work was important to this thesis. The first

of these is Dr. Peter Bicknell of Monash University who provided advice

on the question of the colour of Sirius. The second is Dr. G. P. Goold

whose text and work on Manilius I have relied upon for my own studies.

Errata

Since the original printing of this thesis a number of minor errors have

been found and corrected:

Chapter 5 - ‘pg’ removed from the footer.

Bibliography - Iliad spelt Iliad in Richardsons The Iliad: A Commentary.

We all miss you

Preface

The principal goal of my thesis will be to examine the astronomy found

in the Astronomica of Manilius. Little of the astronomy of the ancient

world has survived. Manilius preserves some clues and facts that provide

an insight into this field. There are also a number of other topics that I

feel deserve re-examination, the best of these is the question of the date

of the work. With this emphasis I have not examined the areas of the

literary or linguistic worth of the poem.

Before looking at the poem in detail it is first advisable to review the

work overall. The Astronomica is a poem in five Books, written by the

Roman poet Manilius c. A.D. 14. It is approximately 4,250 lines in length

and is one of the few extant works that deals with astrology. Woven

through the astrology is the central theme of the work, that of Stoic

philosophy, as well as a significant amount of astronomical information.

The Astronomica provides no intensely detailed account of any aspect of

its subject matter, be it astrology, astronomy or even Stoicism. The Stoic

content of the work does present a consistent argument, but there is no

serious debate nor discussion of the various aspects of the philosophy as

might be found in the works of the earlier Stoics. Manilius’ poem was

clearly not intended to be an analytical examination of Stoicism. Its goal

was to convince the reader of the worth of Stoicism and to reveal the

divine future to the few willing and able to learn its secrets. Indeed, the

______________________Preface 11

astrological worth of the Astronomica is limited. Although astrology

astrological worth of the Astronomica is limited. Although astrology

comprises the bulk of the text, analysis reveals that it is merely a number

of incomplete and contradictory summaries of astrological procedures.

The astronomical content is included merely as introductory material to

the astrological.

My thesis comprises six chapters: an Introductory chapter that examines

the Astronomica itself, a second chapter that looks at the world of the

poet Manilius, a third chapter on the astronomy inherent in the Astronomica,

a chapter devoted to a case study on the colour of the star Sirius in

antiquity – a study that clearly reveals the usefulness of Manilius as a

source for astronomy, a fifth chapter that examines the Stoic origin of

Manilius’ astrology and a final chapter that takes a detailed look at the

major astrological procedure offered by Manilius.

The first Appendix is a glossary of astronomical and astrological terms.

These terms are explained in my footnotes, but Appendix A provides a

more detailed explanation of all terms used. Appendix B is a list of the

constellations appearing in the works of both Aratus and Manilius.

______________________Stoicism, Astrology, Astronomy and the Meaningof the Astronomica 12

1. Chapter One: An Examination of the Astronomica

1.1 Stoicism, Astrology, Astronomy and the Meaning of the

Astronomica

The purpose of Manilius’ work, an overarching framework of Stoicism,

required that a diverse range of material be incorporated into the text.

These included: Greek astronomy, Greek and Roman historical events,

mathematics, astrological procedures, praise of the Imperial system, appeals

to the reader’s vanity and an attempt at scientific rationality. The goal of

such a copious mix was to convince the reader that Stoicism was the

correct means by which to comprehend life and destiny.

We can begin our examination with the assumption that Manilius saw his

work as the ultimate document of humanity and as a product of the ‘new’

Augustan golden age, demonstrating his belief that everything could be

understood and explained within the belief system of Stoic astrology.

Manilius constructed the work, utilising the knowledge and background

of the contemporary Graeco-Roman world, to explain his beliefs

progressively over the course of his poem.

He began this task by devoting Book One to an introductory account of

astronomy, a subject that he believed first had to be understood before

one could encompass astrology. He also introduced Stoicism and astrology,

but in lesser detail, and he included several laudatory references to Augustus


and the Imperial system. Perhaps as an indication of Manilius’ true goals,

and the Imperial system. Perhaps as an indication of Manilius’ true goals,

the number of references to the Imperial system declines rapidly after

Book One. His interest is Stoicism, and everything else, including Augustus,

plays a secondary role.

Book Two is devoted to astrology and opens with a declaration that all

earlier poets are now redundant and that Manilius alone composes on a

subject of worth. These opening lines also include the first detailed look

at his Stoicism. Here he states that God1 is one with, and controls, the

universe; that it is this control that makes astrology possible, as a reciprocity

exists between the heavens and the Earth. These are the beliefs that Book

Two is designed to convey. After a prooemium of one hundred and forty-nine

lines, the remainder of the Book contains a number of incomplete summaries

of astrological practices, which are presumably not intended to turn the

reader into a practising astrologer, rather to impress with the complexities

of astrological theory and Stoic belief.

This is the model followed in Books Three and Four, each of which

Manilius introduces with short, but detailed accounts of Stoicism. In Book

Three he repeats the introduction of Book Two but in greater detail. The

prooemium of Book Three emphasises the unique nature of the poem and

Stoic belief in the central role of God, the existence of fixed laws and the

reciprocity between the different components of the universe. The remainder

of the Book is devoted to a complex but flawed account of astrological

procedures. These are, once again, not designed to turn the reader into an

astrologer, but to bolster the validity of the Stoic statements by an

overwhelming display of astrological practice.


1 For the sake of clarity I shall use the following style when discussing the various‘gods’ found in the text: the Stoic God will be referred to as ‘God’ while the traditionalRoman and Greek Gods will be referred to simply as ‘gods’.

Book Four begins with a description of the futility of seeking wealth and

power and of the importance of Fate, and the history of the rise of Rome

is used as proof that Fate controls human accomplishment. There follow

700 lines of astrological theory. Book Four differs from the first two

astrological Books in that it contains a peroration, which repeats the

message that Fate is all-powerful, and it is stated clearly, for the first time

in the Astronomica, that human beings are divine; that they can become

part of the Stoic God; and that God wishes human beings to know of this

potential. This is the central argument of the Astronomica. Everything

else in the poem is designed to lead to this conclusion.

In Book Four Manilius completes his philosophical discussion. As a means

of conveying the thesis of the Astronomica Book Five is irrelevant, since

it merely contains additional accounts of astrological theory. For this

reason I suggest that Book Four was originally intended as the concluding

Book of the work.

If examined at a detailed level the Astronomica seems poorly structured

and even incomplete, but this conclusion is only viable when the author’s

own goal is not taken into consideration. The work was intended to convince

the reader of the worth of Stoicism, nothing more. To this end Manilius

grouped together such a diverse range of material, designed, both inform

and to impress the reader. He had one goal, to lead the reader to the

conclusion that the peroration of Book Four contained the ultimate truth.

__________________Summary of the Astronomica of Manilius 15

1.2 Summary of the Astronomica of Manilius

1.2.1 Introduction

This summary will review the background and provide an outline of the

Books of the Astronomica as well as prefigure the major conclusions of

this thesis. I shall be relying primarily on the text of G. P. Goold, published

in 1985 by Teubner, which follows, in the main, the A. E. Housman text.

No complete copy of the work exists.2 There are a total of twenty-two

MSS, of which only three are significant, but from these we possess a

near intact text. Only a handful of lines is missing from Book One, and

approximately one hundred and seventy-six lines from Book Five. The

subject of each lacuna can be reconstructed without great difficulty. The

tradition that there were more than five books is unsubstantiated.3 The

different MSS contain a variety of authors’ names: Mallius, Manlius and

even Boethius and Aratus. The first two can be attributed to a copyist’s

error, the last two to errors in identifying the manuscript. The name of the

author of the Astronomica was Marcus Manilius. While there is a question

as to the precise date of the work, it is reasonable to conclude that it was

composed c. 14 A.D. This topic will be examined in thesis section 1.3.


2 This discussion is intended to provide merely a brief background of the history ofthe work and its editors; see Housman (1937) vii–lxxv, Garrod (1911) xv–xcix andDuff (1960-1) 450–54 for more detail.3 This question is discussed by Gain (1970) 128–32 and Thielscher (1956) 353–72.Maranini (1994) 39-42 discusses the possibility of there being six books in theAstronomica. The reason she advances for this is Manilius’ desire to emulate the sixbooks of Lucretius’ De Rerum Natura. I have found no evidence for this possibility inthe text and cannot agree with this possibility. I might add that the average length ofeach book in Lucretius is approximately 1250 lines while the average in Manilius isapproximately 900 lines. If Manilius was concerned about the number of books hewould also have been concerned about the length.

Manilius clearly intended his work to convince the reader of the central

role and worth of Stoicism in life and destiny. The Astronomica has been

referred to as a didactic, astrological poem.4 This is understandable, but it

may be more accurate to refer to it as a proselytising, Stoic poem. The

nature of the work suggests that Manilius was not primarily attempting to

create a work of scholarship or even of poetic significance, rather to

convince his readers of the validity of his version of Stoicism.5 In antiquity

the work received little attention.6

The theme of Stoicism consumes deceptively little space in the Astronomica,

but this brevity disguises its true importance. The Stoic position Manilius

outlines ranges from the formation of the universe to astrology and human

destiny. These ideas reach a culmination in the conclusion to Book Four,

which is presented with logic, care and skill. Over the course of the work

each aspect of the case is clearly set out and subsequently used as a


4 This is a commonly found belief. The Oxford Classical Dictionary (1996) 917-8begins its description of the Astronomica with this statement.5 Manilius’ worth as a poet is a matter of some debate. He has been criticised bySikes 178 as inferior to Lucretius. Quinn (1979) 121 states he is ‘dull’ and thatHousman ‘squandered half a lifetime’. Alternatively, Fletcher (1973) 137 has praisedthe content of this poem and compares Manilius favourably to Ovid.6 Goold (1977) xiv provides a list of authors whose work may have been influencedby the Astronomica, but he suggests that the degree of influence was minor. AlsoLapidge 1393 states that later Roman Stoic cosmological authors followed Manilius’example. I feel that it is more likely that the similarity between Manilius and laterwriters originated in their use of the same Greek sources rather than of Manilius.In the Medieval world the Astronomica was mentioned a number of times, but there isno indication that it achieved any great degree of recognition. The first modernversion of the text was by the astronomer/astrologer Regiomontanus in the latefifteenth century. Scaliger also edited the text in 1579. In 1674 Sir Edward Sherburneproduced the first complete English translation. In 1739 Bentley’s edition waspublished. The next major editor was A. E. Housman whose editing and commentary onthe text is the latest and most widely respected example of Manilian scholarship. Thelatest English translation is by G.P. Goold for the Loeb Classical Library, publishedin 1977, accompanied for the most part by a text that follows Housman. The latestpublished text is by G.P. Goold for Teubner in 1985.

‘building block’ to support the argument. Manilius reinforces his case by

‘building block’ to support the argument. Manilius reinforces his case by

repetition and by analysing the evidence from different perspectives.

Essentially, he constructs a narrative, interspersed with astrological theory

over Books One to Four, to illustrate the nature of his Stoicism. By this

means the reader is confronted with a well-crafted and convincing argument.

The astrological content of the Astronomica, though it constitutes the

bulk of the work, may be considered merely a vehicle to transport the

Stoic philosophy of Manilius.

In contrast to the concise and well-reasoned account of Stoicism, the

description of astrology is rambling, inadequate and in seeming

contradiction to his stated objective of providing the reader with the

means to predict the future by astrology. Even more surprising is the fact

that the accounts and summaries of astrological theories and practices

described are incomplete and mutually exclusive.7 Manilius does not present

a systematic account of a single astrological method, nor an analysis of

existing methods in order to determine the best, rather he gives us a

mixture of partly unrelated and contradictory beliefs, with an emphasis on

the theoretical side of the astrological methods he describes. It is clear

that Manilius did not intend to provide a practical guide to prediction,

rather to summarise (or perhaps merely list) what were possibly the

prominent astrological beliefs of his time, without any attempt at their

reconciliation.

Included amongst Manilius’ astrological discussions is a significant amount

of information on astronomy. Most of the earlier Greek astronomical


7 Quinn (1979) 126 argues that didactic poets did not concern themselves with thequestion of accuracy, merely with style and appeal. This seems to be the case withManilius’ astrology but not his Stoicism.8 Sextus Empiricus 5.1–3 (c. 200 A.D.) clearly differentiates between astrologyand astronomy in his introduction to Adversus Astrologos, using these two terms andexamples.

texts have been lost and much of our knowledge is found in the Almagest.8

texts have been lost and much of our knowledge is found in the Almagest.8

The Astronomica also contains a summary of astronomy, a century and a

half earlier than the Almagest, which is of use in ascertaining the

development of astronomy in the ancient world.

The title of the work, Astronomica, is also indicative of Manilius’ intent,

to discuss astronomical topics. Although the term astrologia was in common

use for astrology and astronomia for astronomical works,9 and although

Manilius was writing of astrology, he avoided use of the term astrologia

and its cognates. Manilius’ title Astronomica, implies that the work

possesses a solid basis for belief, distinct from traditional belief in the

gods and distinct again from the taint of common astrology.10

The following summary of the Astronomica lists the major points of each

Book and the conclusions drawn from them.

1.2.2 Book One

The major objective of Book One is to provide an introduction to the

Astronomica by presenting an above average level of non-mathematical

astronomical knowledge and the basics of Stoicism to the reader. It does

not include any astrological procedures, an omission which suggests that

Manilius believed that a basic knowledge of astronomy was needed before


9 The Almagest was written by Claudius Ptolemy in the second century A.D. It is themajor extant work on astronomy surviving from the ancient world, cf. thesis section2.1.4.10 Goold (1977) xi-xii concludes that there is no doubt as to the authenticity of thetitle, and suggests that Manilius was emulating Virgil’s Georgics when he named hiswork the Astronomica, cf. Sikes (1923) 174ff.

one could move onto the intricacies of astrology. The major theme of the

one could move onto the intricacies of astrology. The major theme of the

Astronomica, Stoic astrology, is discussed only briefly, but its importance

is stressed.

Book One appears the most organised of the five Books. It performs its

introductory duties in a concise and cumulative fashion, beginning with

the formation of the universe and proceeding to explain each aspect of the

heavens in turn.11 The greater part of the text expounds astronomical

background, but Stoicism is used to justify the nature of the universe as

described by astronomy. In this fashion Manilius’ explanation of astronomy

reinforces his philosophical views.

The Book begins with a statement of intent, that the poem is designed to

inform human beings of their fate by giving them knowledge of astrology

(1.1–3). Manilius also makes a claim to originality (1.4), a claim repeated

at intervals throughout the Astronomica.12 The opening lines also include

a dedication to ‘Caesar’ (most probably Augustus) 1.7ff.:

hunc mihi tu, Caesar, patriae princepsque paterque,

qui regis augustis parentem legibus orbem

concessumque patri mundum deus ipse mereris,

das animum viresque facis ad tanta canenda.

This dedication sets the political tone of the Astronomica. Manilius gives

support to the Imperial regime, praising it here and at later points in Book

One, and in the remainder of the Astronomica. Book One also provides a

brief history of astrology, crediting its discovery to the god Mercury who,


11 Ovid preserves his own brief introduction to the history of astrology in Fasti1.295. He echoes the Manilian theme that the study of the heavens is the most nobleof callings but otherwise differs in tone and content from Manilius.12 In the opening lines of Books One, Two, Three and Five, and in 4.117–8.

Manilius claims, gave the gift of this art to humanity via the Babylonians,

Manilius claims, gave the gift of this art to humanity via the Babylonians,

who in turn reputedly taught it to the Greeks and Romans (1.25–117).13

After starting his account of the universe, Manilius introduces cosmology

and astronomy, first explaining how the universe came into existence,

and then describing its structure (1.118–254). He lists seven cosmological

theories, the last being the Stoic theory that the Earth is the centre of a

universe composed of the four elements, air, fire, sea and land.14 In the

remainder of the work, Stoic theory is given precedence and is assumed

to be correct. Manilius’ belief in the Stoic system is manifestly evident

throughout the Astronomica. On several occasions he mentions rival

philosophies but always to contrast them unfavourably with Stoicism. In

Book One he seizes two opportunities to criticise Lucretius and

Epicureanism (1.483ff. and 1.530ff.).15

Having dealt with the necessary preliminaries, Manilius now reaches the

stage of providing a detailed astronomical description of the heavens. He

begins with an catalogue of the constellations. In 1.255–531, forty-four

are listed, with the twelve zodiacal signs presented first, then the northern

and southern constellations. After this, there is a brief mention of the

planets (1.538, 1.805–808),16 followed by a list and description of eleven

celestial circles (1.539–804). Book One concludes with a somewhat

rambling description of comets and meteors (1.809–872).


13 In line 1.30 Manilius invokes Mercury as tu princeps auctorque sacri, Cyllenie,tanti. This is a literary reference to Mercury, who, as the messenger of the Godscarried the gift of the Gods to human beings (1.26), although the use of the terms‘auctor’ and ‘princeps’, seem to describe more than merely a messenger. They suggestthat Mercury was the creator, or deity, in charge of the science of astrology—the Godof Astrology.14 The other theories are those of Xenophanes, Hesiod, Leucippus, Heraclitus, Thalesand Empedocles.15 cf. Manilius’ Stoicism in thesis section 2.7 for an examination of this topic.16 A total of 5 consecutive lines: 538, 805, 806, 807, 808 following Goold’s text.

This introduction is a reasonable successful attempt at a non-mathematical

summary of ancient astronomy. Manilius describes what could be called

the ‘standard model’ for the classical world, a geo-centric system with the

planets, the Sun, Moon and stars circling the Earth.17

On the other hand, although Book One is intended to provide the reader

with sufficient information to comprehend the often-difficult reasoning of

subsequent Books, in this endeavour it is only moderately successful. The

astronomical discussion covers topics that are of no relevance to the later

astrological procedures, while there is inadequate coverage of areas

necessary for an understanding of astrological theory.18 Much additional

information could have been included (e.g. more information on the planets,

an explanation of the measurement of time), if only for the sake of

completeness. Manilius’ omission of necessary information is difficult to

comprehend unless we assume that it was merely a framework for his

version of Stoic destiny in which the precise details were unimportant.19

The other major theme of Book One is Stoicism. Here Manilius demonstrates

his skill, since the discussion of Stoicism is argued convincingly, forming

an effective basis for the philosophical theory found in later Books. Book


17 Ptolemy Claudius’ description of the universe in the Almagest provides the mostdetailed account of classical astronomy. For a modern discussion of this model seeNeugebauer (1975) 2-14 and 145-256.18 For example, there is an extensive account of the celestial circles in Book One.While some of these circles have a degree of relevance to astrology, others do not. Nordoes Manilius explain the 360 degree system, which would be of use in the astrologicalBooks. In a similar fashion, the detailed account of the non-zodiacal constellations(except for Book Five) and of comets and meteors is not needed for any astrologicalpurpose.19 It should be understood, however, that due to the varied and discordant nature ofthe astrological procedures in the Astronomica, it would be difficult (but notimpossible) to create a firm astronomical basis for the work.

One outlines clearly the themes of a single god, the dominance of fate

One outlines clearly the themes of a single god, the dominance of fate

and of the holistic nature of the universe.

1.2.3 Book Two

Book Two is the first of Manilius’ ‘astrological’ books and the longest

book of the Astronomica (970 lines). It begins Manilius’ account of a

diverse range of astrological procedures centred on the zodiac, and it

offers a framework on which to expound his view of Stoicism.

The first lines (1–59) are largely a dismissive summary of the ‘mythical’

poets from Hesiod to his own times, with an introductory mention of

Homer.20 Manilius places each author and work in a historical context

and concludes with the claim that his own work is original. The implication

is that the Astronomica, a work of Stoicism, is the culmination of the

poetic, didactic genre and that Manilius should be viewed as the leading

exponent of a form of Stoicism, the function of which is to explain the

nature of the universe to those chosen by fate to understand it.21

The introduction is followed by a narrow, but detailed account of Stoic

philosophy (2.60–135). Manilius explains that God created and controls

the universe and that astrology is a direct consequence of God’s existence.

The poem implies that human beings are semi-divine. This account builds

on the Stoic references made in Book One, and acts to reinforce the

validity of these beliefs in the mind of the reader. The introduction concludes

with a statement by Manilius that the study of Stoic astrology is a lonely


20 Quinn (1979) 125 states that the epic poem had fallen into disfavour in the lateHellenistic period while the didactic poem had increased in popularity.21 It is clear that Manilius saw the Astronomica as a work of primary importance,which combined with his lack of mention of any other Stoic figure suggests that hesaw himself as the leading (if not the ultimate) figure in Stoicism.

task and, while others pursue wealth and power, the poet alone pursues

task and, while others pursue wealth and power, the poet alone pursues

knowledge (2.137–49).

The remainder of Book Two is a detailed explanation of the zodiac.

Manilius begins by listing the nature of individual zodiacal constellations

(hereafter referred to as signs): male/female, single/double, rise angle,

diurnal/nocturnal, aquatic, fertility, posture and disfigurement

(2.150–269).22 These are allocated to seasons. Next, the relationship

between each is explained (2.270–432). The zodiac is depicted as laid out

in a circle with various geometric shapes (triangle, square, hexagon) linking

respective constellations. Following this, signs are allocated to gods and

then to parts of the body (2.433–65). The narrative then returns to signs

and shapes by listing relationships created by parallel lines drawn between

them (2.477–692). With this, the text moves to divisions within the zodiac.

Each sign is divided into twelve divisions (referred to as a dodecatemory)

of two and a half degrees with each division allotted to another sign

(2.693–737). This process of division continues with planetary

dodecatemories. The dodecatemory of each sign (two and a half degrees)

is divided into five parts (half a degree) and each of the five planets is

allocated one of these divisions of half a degree (2.738–48).

The zodiac is then placed within a framework, based upon four fixed

cardinal points and the space between them, through which the stars

move on their continual revolution around the Earth (2.788–855). These

areas are said to modify the influence of their proximate signs. Manilius

then introduces ‘Temples’, which are the twelve divisions of the zodiac

that have no stellar counterpart. These creations are based on the position

of the cardinal points. The influence of each zodiacal sign is said to be

modified as it passes through each ‘Temple’ (2.856–967). The concluding


22 These last two points are unique to Manilius (Goold 1977, xl.).

lines of this section refer to the modifying influence of the planets on the

lines of this section refer to the modifying influence of the planets on the

‘Temples’. Manilius states that he will discuss the role of the planets in

astrology later in the Astronomica, and although this promise is repeated

elsewhere it is never fulfilled.23

The poem implies that the planets exercise little influence on the affairs

of human beings, a position seemingly at odds with our few other extant

accounts of ancient astrology which give precedence to the planets.24 In

an attempt to reconcile these two astrological traditions I can only suggest

that Manilius may have preferred the zodiac as the vehicle for prediction

because it was the ‘roof of the heaven’, since it lay furthest from the

Earth and thus was more ‘perfect’ than the planets.

Manilius’ explanation of the role of the zodiac would be entirely inadequate

for any practitioner of the art of astrology. He provides an overview of its

various astrological influences but gives no detailed account of their

interrelationship, nor any indication of how these influences are to be

combined into a prediction. The astrological information presented here

seems little more than selections from various astrological procedures

rewritten into one text. Although Manilius’ stated aim is to provide the

means by which human beings can understand their future, neither Book

Two, nor any of the subsequent Books, provides the means to cast

predictions.25


23 2.750, 2.965, 3.156–8, 3.587.24 There are a number of lines missing from Book Five. Goold (1977) xcvii-c, 358suggests that approximately 176 lines are missing (including chapter headings) andthat these lines may have discussed the role of the planets in astrology. If thisassumption is correct, Manilius leaves the definitive discussion of the planets to thelast section of the last Book, and to fewer than 200 lines, suggesting that he did notplace great importance upon the planets. In contrast, Ptolemy in the Tetrabiblos,devotes approximately 250 lines in his introduction to a summary of the role of theplanets. The planets are then referred to throughout his text as an intrinsic featureof astrological influence.

In Book Two Manilius deems it necessary to explain his didactic procedure

(2.750–87), stating that one must first learn the simplest elements of a

belief then build incrementally on this existing knowledge. He uses the

simile of the construction of a city to illustrate his view. This is one of the

few ‘biographical’ references in the Astronomica, providing a glimpse of

the poet’s approach, with the lines skilfully merged with the narrative.

This didactic method is evident in his account of astrology and even more

so in his discussions of Stoicism.

The Stoic content of Book Two (2.60–149) differs markedly from the

sections dealing with astrology, in that it covers a great deal of ground

and presents a solid argument to the reader. It is concisely written, well

reasoned and logically presented. It begins with God and concludes with

a Stoic justification of astrology. This account also supports the narrative,

since it links the preceding discussion of poetry with the astrological

section of Book Two immediately following. The clarity of the presentation

of the Stoic section of this Book is in contrast to the inadequate presentation

of the astrological section.

This second Book provides a model for Books Three and Four. It contains

a plethora of astrological detail and a wide range of potential influences

for an astrologer to explore, yet the practical task of casting a prediction

is ignored. In Books Three and Four other astrological theories are developed

which are equally detailed and equally incomplete. They bear no relation

to those of Book Two and even contradict them (and each other). Through

all this the discussion of Stoicism is carried forward skilfully over the


25 This is in contrast to 1.25ff. where Manilius recounts the history of astrologywith the theme that gaining an understanding of the heavens is the principal goal ofhuman progress. This initial claim, that astrology is of primary importance, isignored in the text itself.

course of each Book.

course of each Book.

1.2.4 Book Three

Book Three provides a second detailed account of astrology. The reader

is introduced to several new astrological principles and techniques, but

there is a stylistic departure from the earlier Books with the inclusion of a

number of mathematical formulae which are used to calculate a horoscope.

This is the sole use of formulae in the poem.

Manilius begins Book Three by re-stating that his work is both original

and intrinsically difficult, while the work of other poets, on wars and

nations, is comparatively easy (3.1–42), a theme he referred to in the

introduction to Book Two.26 He also includes several editorial lines in

which he laments the difficulty of rendering numbers and unusual concepts

into verse (3.40–2).27 This statement is particularly apt as Book Three

does contain complex formulae.

After identifying the importance of his work, Manilius provides a few

lines on Stoic cosmology (3.43–66), which pick up the philosophical

account begun in Books One and Two. He begins by invoking Stoicism

as a justification for astrology, and proceeds to prove this by recounting


26 Goold (1977) lxii lists 3.23–5 as Manilius’ solitary reference to Roman literature,the Annals of Ennius. The reference may have been motivated by Ennius’ discussion ofastrology (Cic. Rep. 1.18.30) and the possibility that he may have been the earliestLatin author to compose on the topic. If so, this was no more than a minor referenceto astrology presaging its greater importance in the next century.Cicero makes a similar statement about poets in which he refers to their work asdelirantium somnia (de Nat. Deorum 1.42). Criticising poets was not confined toManilius or to Stoics.27 An alternative view is offered by Quinn (1979) 122-3 who suggests that it waseasier to compose in verse than in prose. This is a question that cannot be easilyanswered. I would suggest that the relative ease of both forms may rely more on thewriter’s innate abilities and skills than any other factor.

the nature of the Stoic universe. He describes a geo-centric universe of

the nature of the Stoic universe. He describes a geo-centric universe of

centralised order where each component is in equilibrium and harmony,

governed by the laws of nature (3.43–60). The concept that an event in

the heavens and an event on the Earth are manifestations of the same

underlying cause and that the latter can be predicted by the former is the

Stoic basis of astrology.

Manilius’ proof of astrology is that stars intrinsically control human destiny

(3.60ff.). This leads into the central importance of the zodiac, which in

turn leads into an account of athla.28 These are twelve divisions of the

zodiac, each of 30 degrees, which control different aspects of life

(3.61–159). They independently rotate in a fixed order following the path

of the zodiac. The task before the diligent astrologer is to locate the

position of the athla at the moment of birth. An inadequate explanation of

how this is achieved consumes half of Book Three (3.160–509). Manilius

describes several different formulae for this purpose, with a mixture of

clarity and confusion, before reaching what he considers the valid version.

These formulae are relics of earlier astronomical theories, possibly of

Babylonian origin.29 They are ‘rule-of-thumb’ formulae that calculate the

changing rise-times and set-times of the zodiacal constellations. While

they are adequate for this task, they themselves can only be part of a

larger procedure that was required to calculate the position of the athla,

but this procedure has not been provided. Thus everything described in

Book Three is largely irrelevant, certainly of no use to those who wished

to learn how to use the athla to cast a prediction. So continues the marked

contrast between Manilius’ clarity in his accounts of Stoicism and his


28 Manilius uses a Greek term, 3.162, perhaps an indication that he has turned toyet another source (Goold 1977 lxii). As Goold points out, the concept of Athlacontradicts the astrological procedures detailed in Book Two.29 See chapter Six, cf Goold lxiv–v.

almost obfuscatory approach to astrology.

almost obfuscatory approach to astrology.

In the final section of Book Three, Manilius describes a new astrological

procedure, that of ‘Chronocrators’ (3.510–59).30 These are allocations of

portions of a life to astrological influences. Their utility to a student of

astrology is limited by their incompatibility with the previously described

athla and by Manilius’ description of two mutually exclusive means of

determining which influences are dominant. Following this, Manilius

describes how the zodiac determines the length of human life (3.560–617),

and how each sign gives those under its influence a different life-span.

The final lines of Book Three describe the powers of the four ‘tropic’

signs (Cancer, Libra, Capricorn and Aries) in which the seasons change

and the two solstices and two equinoxes reside. Manilius states that these

have great power but does not elaborate (3.618–682). He concludes this

account, and Book Three, by noting that the unstated powers of these

signs are controlled by either the 1st, 8th or 10th degree points of each

sign. Thus he effectively negates what he has just described (if not the

bulk of the astrological theory in the Astronomica) by claiming that the

‘starting-point’ for calculating the powers of the ‘tropic’ signs is unknown.31

Book Three repeats the format of Book Two but with less consistency–the

various items of astrological theory are each irrelevant to the others and


30 Manilius himself does not name them, but they are so named by Goold (1977,lxxvii–lxxviii).31 I did attempt to discover which degree Manilius himself uses by analysing theparanatellonta of Book Five. Only one of these provides sufficient detail to enable anaccurate positional determination, 5.197ff., which states that Procyon rises in the27th degree of Cancer. When Procyon is on the eastern horizon (assuming the latitudeof Rome), the ecliptic is 102 degrees distant from the First Point (assuming that theFirst Point of Aries is measured at the local epoch, e.g. 10 degrees south of BetaAries). This gives a figure of 12 degrees for Cancer. To reach the 27th degreerequires the assumption that Manilius took the 15th degree of each constellation asits starting point, a position not canvassed anywhere in the Astronomica. Book Fivedoes not shed any light upon this question.

are internally inconsistent. Again the stated aim of the Book is to enable

are internally inconsistent. Again the stated aim of the Book is to enable

the student to cast predictions (3.43ff.), but insufficient information is

provided to achieve this objective. From an astronomical perspective, our

interest in Book Three lies in the ‘horoscope’ formulae that almost certainly

contain astronomical procedures from the late Babylonian period of

astronomy. In his presentation of Stoicism, on the other hand, Manilius

again shows care and diligence. He repeats the earlier themes of a central

influence and the unchanging order of the heavens.32

1.2.5 Book Four

In Book Four, Manilius continues his discussion of astrology with an

account of the correlation of different parts of the zodiac with different

personal characteristics and a ‘zodiacal’ map of the world where signs are

allocated to different geographical areas. The major worth of Book Four

is the concluding Stoic discourse in which Manilius explains and justifies

the belief that human beings possess a divine nature and destiny.

The prooemium (4.1–118) is a reiteration, in a more detailed form, of the

Stoic arguments put forward in earlier Books. Manilius avers that the

reason for studying Stoic astrology is to gain sufficient knowledge of fate

so as to be able to face the future with fortitude. His main concern is to

confirm and reinforce the belief in the dominance of fate. In doing this

Manilius uses numerous examples from Roman and Greek history.

After the prooemium Manilius returns to his account of astrology. In

4.122–293, he grants to each of the twelve zodiacal signs an influence

over the career and profession of those born under their authority. In


32 1.247–54, 2.60–135, 3.48–55, 4.886–935.

4.294–407 Manilius explains how these influences are further subdivided

4.294–407 Manilius explains how these influences are further subdivided

to correspond with the division of each sign into three units. Each of

these divisions, of 10 degrees, is said to modify the influence of the sign

as a whole and further modify human character. He claims that the seeming

randomness of human behaviour is merely an illusion created by our lack

of understanding of the complexity of astrology (4.373ff.). He explains

the powers of individual degrees of the zodiac (4.408–502), and the measure

of influence of specific parts of each sign (4.503–84).

The next discussion concerns the relationship between geographical areas

and zodiacal signs (4.585–817). Here is included a description of the

world and of the characteristics of different regional populations and a list

of different regions with their respective zodiacal sign. The astrological

discussion concludes with the effect of Lunar eclipses (4.818–65), which

allegedly weaken the power of the sign within which they occur. This

discussion contains a reference to Tiberius which suggests that he was

emperor while the later Books were being composed (4.763-6).

Book Four is brought to a close by a return to the argument put forward

in the introduction. Manilius now explains how knowledge of the universe,

fate, the fact of human divinity and the unique nature of human beings

have all been created by the Stoic God and are intrinsic features of the

universe (4.866–935). The goal of human social progress embraces a

divine future. It is clear that the Astronomica was intended to be a the

‘guidebook’ to this future.

The bulk of Book Four comprises descriptions of astrological procedure,

but as with Books Two and Three, these accounts bear little relation to

each other, and there is insufficient detail to render them usable. The


major significance of Book Four lies in its philosophic content. It is here

major significance of Book Four lies in its philosophic content. It is here

that Manilius concludes his discussion of Stoicism with a well-reasoned

argument in favour of Stoic principles and destiny.

The tone of this section and the specific statement, iam nusquam natura

latet; pervidimus omnem (4.883), suggest that the Astronomica was

originally brought to a close at this point. Books One and Four conclude

with perorations, both of which dedicate the poem to Stoicism and to

‘Caesar’. Within the first four Books there is a clear pattern of development.

Book One provides the introduction; Books Two and Three continue the

account of Stoicism, as well as a supporting description of astrology; and

Book Four concludes the Stoic account of the universe.

1.2.6 Book Five

Book Five differs substantially from the first four Books in that it contains

no reference to Stoicism. Its astrological content is also less complex and

less mathematically grounded than that in Books Two, Three and Four,

and it contains a higher proportion of myth. The treatment of astrology in

Book Five also differs from the previous Books, since it is based upon the

non-zodiacal constellations.

The motive for Manilius having composed Book Five is unclear, since

the stated aim of the Astronomica has been reached in Book Four. The

opening lines in Book Five, however, offer a clue. Here, Manilius says

that other authors would have completed their work at the end of Book

Four, but he, however, feels that the poem would be incomplete without a

discussion of the astrological influence of the non-zodiacal constellations

(5.1–31). Manilius may have felt compelled to complete the summary of


what he believed were the important, non-planetary astrological theories

what he believed were the important, non-planetary astrological theories

of his day,33 but this does not answer the question of why Stoicism has

been excluded from this Book. Perhaps the poem originally ended with

Book Four and Book Five was added at a later date, as an afterthought.

Discussion of the non-zodiacal constellations consumes most of Book

Five,34 and involves a listing of the rising-times of non-zodiacal stars with

individual degrees of zodiacal signs.35 Each group of stars is said to

produce a different personality for those born under its influence, a system

incompatible with any of the astrological systems outlined in Books Two,

Three or Four. Nor, like the earlier systems, is it presented in sufficient

detail to be of practical use to a reader. Near the end of Book Five

Manilius gives his long-promised explanation of the effect of planetary

influences on astrology, but, unfortunately, most of this has been lost.36

Following the discussion of the planets in Book Five, Manilius categorises

the constellations in a Hipparchian magnitude system.37 Unfortunately,

only twenty-three lines of this section survive, but these are enough to

identify its nature and content, and to provide the earliest extant account

of the stellar magnitude system. A similar description can also be found

in the Almagest, where it is used in Ptolemy’s stellar catalogue. There has

been some debate38 as to whether Hipparchus or Ptolemy created both the

magnitude system and the first stellar catalogue, but its use by Manilius


33 As discussed, Manilius evidently did not consider ‘planetary’ astrological theoriesimportant.34 677 lines in total (5.32–709).35 Stars which rise and set at the same time as sections of the zodiac are referred toas ‘Paranatellonta’.36 Goold (1977) cvii, 358.37 This system divides the stars into six categories of brightness: 1st brightest—6thfaintest.38 thesis section 3.6.

demonstrates that the system pre-dates Ptolemy and thus that Hipparchus

demonstrates that the system pre-dates Ptolemy and thus that Hipparchus

was the originator of the first stellar catalogue and of the magnitude

system.

The last lines of Book Five (734–45) provide a glimpse of Manilius’ view

of society. In the poem, Manilius supports the Roman social system and

uses his philosophy to validate this order. He compares the relative

brightness of the stars, their order and hierarchy, to the social hierarchy of

a city, with plebeians, equites and the Senate. By using this heavenly

analogue, Manilius justifies contemporary social division.39

Book Five ends abruptly. It has been suggested that the text is incomplete,

since it differs in length from Book Two, the longest of the poem, by over

two hundred lines.40 This is not, however, sufficient ground for suspecting

that Book Five is incomplete, since it is not as short as Book Three (682

lines). The conclusion to Book Five is no more abrupt than that of Books

Two and Three, so it is entirely possible that the author, having found

social order in the stars, completed his work with the lines that we now

have.

__________________The Date of the Astronomica 34

39 cf. Schofield (1991) 93-4 .40 Conte (1994) 428.

1.3 The Date of the Astronomica

1.3.1 Introduction

It is agreed that the Astronomica was composed in the first quarter of the

first century A.D., but the precise date of the poem has been a matter of

some debate. The text itself refers to only two specific relevant historical

occasions.41 The date of the poem depends, therefore, on the interpretation

of indirect evidence. Several theories have emerged, one suggests that

Books One and Two were written under Augustus and Books Four and

Five under Tiberius (there is no internal evidence for Book Three).42

Another, and less popular, theory argues that all of the work was composed

under Augustus.43 While a third suggests that the entire work was composed

under Tiberius.44

1.3.2 Summary of Evidence and Arguments

That Book One was written under Augustus is not disputed. There is

abundant internal evidence to confirm this. The frequent references to

Augustus and to the destruction of Varus’ legions are the bases for this

conclusion.45 Thus Manilius may have begun Book One prior to A.D. 9


41 These are the destruction of Varus’ legions by the Germans in A.D. 9 (1.898ff.)and Tiberius’ exile on Rhodes 6 B.C.–A.D. 2 (4.763–6).42 This is presented by Goold (1977) xi–xii, Housman (1913), Kellum (1990)292–3, Garrod (1908-2), Maranini (1994) 31-8.43 Steele (1931) 157–167.44 Bickel (1933) 267 sq.and Gebhardt (1961) 278-286. This last argument assumesthat all of the seeming references to Augustus in Books One and Two were in fact toTiberius, also that the title Pater Patriae , used in Book One, was given informally toTiberius by Maniliius. I do not find these arguments convincing in the face of thestronger evidence in Book One that Augustus was alive during its composition. I willnot pursue this line of research in this thesis.

and perhaps finished it and Book Two not long after that date, as Book

and perhaps finished it and Book Two not long after that date, as Book

Two contains a reference to Augustus implying that he is still alive.46

Book Three contains no evidence of its date of composition, while Book

Five contains only a hint of a much later date, perhaps A.D. 22 (discussed

later). It falls to the astrological references in Book Four to provide clues

as to the date of the work.

There are three passages in Book Four that refer to the emperor. In lines

4.547–52, the emperor’s star sign is given as Libra:47

Sed, cum autumnales coeperunt surgere Chelae,

felix aequato genitus sub pondere Librae.

iudex examen sistet vitaeque necisque

imponetque iugum terris legesque rogabit.

illum urbes et regna trement nutuque regentur

unius et caeli post terras iura manebunt.


45 1.7–10: hunc mihi tu, Caesar, patriae princepsque paterque, / qui regis augustisparentem legibus orbem / concessumque patri mundum deus ipse mereris, 1.385–386:Augusto, sidus nostro qui contigit orbi, / legum nunc terris post caelo maximusauctor. 1.799–800: ...descendit caelo caelumque replebit, / quod reget, Augustus,socio per signa Tonante, 1.898–900: ...foedere rupto / cum fera ductorem rapuitGermania Varum / infectique trium legionum sanguine campos.The inclusion of the destruction of three legions, the worst military disaster ofAugustus’ reign, may seem to be an insult to the emperor, but the emphasis on thedominance of fate does remove the stigma of defeat from Augustus, and Manilius doesmake frequent use of historical events to demonstrate the role of fate. The inclusionof a contemporary event of this importance (indicating the fickleness of fate) suggeststhis usage of historical examples.1.922–926: ...iam bella quiescant / atque adamanteis discordia vincta catenis /aeternos habeat frenos in carcere clausa; / sit pater invictus patriae, sit Roma subillo, / cumque deum caelo dederit non quaerat in orbe.46 2.507–9 ...contra Capricornus in ipsum / convertit visus (quid enim mirabiturille / maius, in Augusti felix cum fulserit ortum?).47 This passage does not refer to an individual by name, but Goold (1977) 266, n. 1states that it does refer to the emperor. Even if this identification is wrong we arestill left with a clear statement that the sign of the emperor (Augustus or Tiberius)is Libra in 4.776–7.

In lines 4.763–6, the island of Rhodes is referred to as the one-time abode

of Caesar:

Virgine sub casta felix terraque marique

est Rhodos, hospitium recturi principis orbem,

tumque domus vere Solis, cui tota sacrata est,

cum caperet lumen magni sub Caesare mundi;

In lines 4.776–7 we are once again told that the emperor’s sign is Libra.

qua genitus Caesar melius nunc condidit urbem

et propriis frenat pendentem nutibus orbem.

The argument that Tiberius is the emperor of Books Four and Five is

based on the reference to Rhodes and the assumption that Augustus’ natal

sign was Capricorn, not Libra, a fact confirmed elsewhere.48 Tiberius had

resided on Rhodes and his sign was Libra.49 In this scenario Manilius was

a late Augustan author who completed his work in the reign of Tiberius


48 Suet. Aug. 94.12: tantam mox fiduciam fati Augustus habuit, ut thema suumuulgauerit nummumque argenteum nota sideris Capricorni, quo natus est, percusserit.Augustus’ affection for Capricorn is shown in a number of different areas. Maniliusrefers to Capricorn as Augustus’ sign (1.375ff, 2.507–9). Germanicus attributesthe sign Capricorn to Augustus (Germ. Phaen. 551–62). Suetonius Aug. 94.12 listsit as Augustus’ birth sign and the sign he placed on his coins. There are a significantnumber of Augustan coins stamped with Capricorn, e.g. RIC 12 (with cornucopiae)and RIC 330 (with globe) etc. Modern sources also comment on Capricorn. Parker262 suggests that Legions II Augusta, XIV Gemina and XXI Rapax contained Capricornon their standards to signify their Augustan origins. Dwyer (1973) 62 suggests thatOctavian used Capricorn as early as the late 40s.49 Housman (1913) (page 870 of the 1972 reprint) states that Queen Pythodorisissued a coin associating Tiberius with Libra. This is also discussed, with the sameconclusion, by Barton (1995) 36. This coin is displayed by Waddington, Balsdon andReinach (1925) 22, coins 20 and 20a. Coin number 19, immediately preceding,displays Augustus and Capricorn.

with the last ‘Augustan’ Book being Book Two or possibly Book Three.

with the last ‘Augustan’ Book being Book Two or possibly Book Three.

1.3.3 The Question of Augustus’ Birth and Sign

We must now discuss Capricorn, since the date of Books One and Two

depends upon the belief that Augustus’ sign was Capricorn and that Tiberius’

was Libra.50 The majority of references suggest that Augustus was a

Capricorn, but these are challenged by the possibility that Augustus may

have also been associated with Libra. There is one clear reference in the

Georgics that Libra was Augustus’ sign. In his dedication to the emperor

Virgil states that a new star shall be made between Virgo and Scorpio for

Augustus. This is the location of Libra (Georg. I.32ff.):

anne novum tardis sidus te mensibus addas,

qua locus Erigonen inter Chelasque sequentis

panditur ipse tibi iam bracchia contrahit ardens

Scorpius et caeli iusta plus parte reliquit;

Thus Libra (Chelae) could be the sign of both emperors, and the Libran

references in Book Four could be to Augustus or to Tiberius. This is the

sole unequivocal statement associating Augustus with Libra. In itself I do

not feel it is conclusive evidence that Augustus used this as a sign. As

Barton suggests it may indicate his future translation to the heavens.51 I

will continue to canvass the possibility of Augustus taking the sign of

Libra, but I do not feel that there is sufficient evidence to state conclusively


50 Suetonius states that Tiberius was born on 16 November 42 B.C. (Tib. 5). As withAugustus, the determination of Tiberius’ ‘sign’ depends on a number of factors andinterpretations; Libra is one possible sign.51 Barton (1995) 35. There is also a reference to the Anthol. Lat. 43 that associates‘Caesar’ with Libra, but the difficulty with this reference is discovering the identityof the Caesar.

that he did so.

that he did so.

The means of answering the question of Augustus’ sign should lie with

his birth date. In Suet. Aug. 5, Augustus is said to have been born pre-sunrise,

23rd September, 63 B.C.:

Natus est Augustus M. Tullius Cicerone C. Antonio conss. VIIII.

Kal. Octob. paulo ante solis exortum.

According to modern sources, this would give Augustus the natal sign of

Libra, not Capricorn as suggested above. Housman’s explanation for this

apparent difficulty is that Capricorn was Augustus’ Lunar sign (the zodiacal

constellation which contained the Moon at the time he was born) and that

Libra was his natal sign (the zodiacal sign rising at his birth)—the more

traditional definition of a person’s sign.52 Housman lists several examples

where the Moon was referred to as an astrological sign rather than the

zodiac,53 so Augustus could have used both Libra and Capricorn as his

sign. It is also possible that Libra was the sign of Augustus’ birth and

Capricorn (the sign the Sun was in nine months earlier) was that of his

conception,54 which would have given Augustus a legitimate claim on

both signs. While this cannot be simply dismissed, there is little evidence

that the Romans considered the date of conception important.

Octavian was born prior to the introduction of the Julian calendar (46


52 Housman (1913) (page 869 of the 1972 reprint). To Manilius, however, althoughthe Moon was an astrologically significant symbol, it was not of critical importance.In 2.726–37 the moon is said to increase a constellation’s influence; in 3.517, theMoon is said to control the months of a life; in 3.590–593 the moon influenceslongevity. Dwyer (1973) 59 suggests that the Lunar sign was of little importanceand therefore could not be the reason for its usage here.53 Cic. de div. 2.91 and 2.98.54 Bowersock (1990) 385, Domenicucci (1993) 214.

B.C.) which he reformed in 9-8 B.C.,55 and it is possible that his sign at

B.C.) which he reformed in 9-8 B.C.,55 and it is possible that his sign at

the actual time of his birth was Capricorn but, after the modifications of

the calendar, that his sign became Libra.56

The sum of this and earlier discussions is that there is sufficient evidence

to suggest that Augustus was primarily associated with Capricorn, but

that for some reason, he also had a minor association with Libra. Given

this, argument for the date of the Astronomica based solely on an analysis

of the emperor’s sign(s) must be inconclusive, yet the weight of evidence

suggests that Capricorn is generally supportive of a reference to Augustus.57

1.3.4 The State of the Heavens

To clarify this discussion, we might take as a reference-point the state of

the heavens at the time of Octavian’s birth. Michels has converted Suetonius’

pre-Julian date of 23rd September 63 B.C., to a range of possible dates,

the 22nd, 23rd and 24th of September 63 B.C. (Julian calendar).58 In

addition to the birthdate there are three astrological determinants that

require consideration: the position of the Sun, the Moon, and the degree

of the zodiac on the horizon. Due to the variability of the ‘schools’ of


55 Samuel (1972) 156-8 discusses the meagre evidence we have of Augustus’ reformof the Julian calendar.56 Bosworth (1982) 151-70 discusses the difficulties and inaccuracies of datingevents in this period.57 This is bolstered by the absence of any significant reference to Libra in Books Oneand Two, the two ‘Augustan’ Books.58 Michels (1967) 180ff.59 As the Astronomica makes clear, there was no single astrological method of castinga prediction; there were in fact many conflicting means of doing so. It is possible tosurmise that there were schools of astrology, each with its own astrological proceduresand theory. To carry this further, it is also possible to speculate that each majorfigure within each school developed his own particular style of astrology and passedit on to his students, who in turn modified their teacher’s style. Barton (1994-1)39 discusses the variety of astrological methods.

ancient astrology,59 any of these could have been used to determine

ancient astrology,59 any of these could have been used to determine

Augustus’ sign, so each of these positions will be calculated for the three

dates suggested by Michels.

For the days in question, the position of the Sun (thus the sign in which

the Sun resides) did not change significantly. The Sun in late September

is in the constellation Virgo (RA 11h 50m, Dec +1 degree)60, near the

bright star Spica. The horizon at 5.00 a.m. (one hour before sunrise)

crossed through the constellation Virgo (RA 11h 20m, Dec +7 degrees).

The Moon was the only astronomical object that changed position

significantly over the three dates. The results of its movement are given

below.

22nd September 63 B.C., 5.00 a.m.

Moon, in the constellation Capricorn (RA 19h, Dec -28 degrees)

23rd September 63 B.C., 5.00 a.m.

Moon, on the border of the constellations Capricorn and Aquarius.

(RA 20h, Dec -26 degrees)

24th September 63 B.C., 5.00 a.m.

Moon, in the constellation Aquarius (RA 21h, Dec -23 degrees)

These are the ‘raw’ astronomical results. To place them (i.e. the position

of the Sun, Moon and the horizon) within an astrological context requires


60 The heavens have been delineated by astronomers into divisions analogous toterrestrial latitude and longitude. RA is Right Ascension, the number of degreeseastwards from the point of the northern intersection of the celestial equator and theecliptic. The degrees of RA are divided into hours, each hour containing 15 degrees,thus there are 24 RA hours in each 24 hour day. Dec is Declination, the number ofdegrees north or south of the celestial equator.

further modification. As Manilius suggests, Roman astrologers may have

further modification. As Manilius suggests, Roman astrologers may have

used an initial starting-point other than the first degree of each sign,

therefore a range of off-sets needs to be determined.61 On the 23rd, the

Sun was 177 degrees from the 1st point of Aries (the starting-point of the

zodiac). This places the Sun within the sign of Libra (150–180 degrees

from Aries). If we assume that the 8th degree of each sign was in common

use, then the Sun was effectively in the 169th degree of the zodiac, still

well inside the sign Libra.

The Moon’s movement amounts to a daily average of 12 degrees (slightly

less than one half of the 30 degree length of a sign). This makes the

determination of the Moon’s position more difficult than the Sun’s. On

the 22nd September the Moon was approximately 285 degrees from the

1st point of Aries; on the 23rd September, approximately 300 degrees; on

the 24th September, approximately 315 degrees. On the 22nd and 23rd,

both with and without the 8 degree offset, the Moon was in the sign of

Capricorn. Only on the 24th did it move into Aquarius.

The horizon is even more variable than the Moon. While the Moon moves

12 degrees per day, the horizon moves 15 degrees per hour. Thus over the

three hour period before sunrise (using the widest interpretation of

Suetonius’ statement that Octavian was born shortly before sunrise) the

horizon line was in the signs Leo, Virgo and Libra (the last at sunrise).

The result of this reconstruction is that Octavian could have chosen a sign

from any of Leo, Virgo, Libra, Capricorn or Aquarius. These results rely

on the accuracy of Suetonius’ statement of Augustus’ date and time of

birth and our interpretation of that date into our system.


61 Astronomica 3.680ff., 1st, 8th and 10th degree of each sign. Bicknell (1989) 97following Brind’ Amour suggests that standard practice was to use the 8th degree.

To this discussion of signs must be added the suggestion put forward by

Tamsyn Barton, who canvasses the opinion that the Roman calendar was

even more irregular than any of its modern chroniclers suggest.62 She

states that Augustus’ birth may have fallen anywhere between July and

December of what is now the Julian calendar.63 This degree of latitude

would also give Augustus a legitimate natal sign of Capricorn

(December/January).

In addition to this irregularity, there is the wide range of astrological

interpretations possible. Ancient astrologers were not interested in

consistency.64 In the verses of Manilius, several conflicting astrological

procedures are presented side by side with no suggestion that the discrepancy

between them is important.65 Attempting to determine the ‘correct’ sign

on the basis of astrological theory alone is impossible.

1.3.5 Rhodes, Tiberius, Libra and Book Four

Since the arguments over Capricorn and Libra have proven inconclusive

we are left with only three references in Book Four to determine the date

of the Astronomica’s composition. These are the the reference to Rhodes

and the subsequent references to Libra and Caesar.

In the first of these references Manilius states that the princeps resided on

Rhodes 4.763–6:66


62 Barton (1995), cf. Samuel 157.63 Barton, op. cit., 36ff.64 ibid., 39.65 Chapter Six discusses the horoscope and gives several examples of this. There isalso the lesser importance given to the planets by Manilius.



est Rhodos, hospitium recturi principis orbem,

tumque domus vere Solis, cui tota sacrata est,

cum caperet lumen magni sub Caesare mundi;

Between 6 B.C. and A.D. 2 the future emperor Tiberius lived in semi-

voluntary exile on the island of Rhodes.67 To a Stoic, the departure into

exile, the possibility of assassination, a return in disgrace followed by the

rapid rise to rulership of the Roman world would indicate nothing more

than the guidance of fate.68 This was the theme, the fickleness of fate, that

Manilius repeated throughout the Astronomica, e.g. fata regunt orbem

4.14. This passage is usually advanced as a retrospective acknowledgement

of Tiberius’ rise to sole power and forms the major argument that Book

Four was written subsequent to Augustus’s death.

It is possible, however, that rather than describing Tiberius’ rule, it could

refer to the future (recturi) assumption by Tiberius of Augustus’ position,

thus dating Book Four to the period A.D. 4–14.69 This interpretation is


66 Manilius does not refer to Tiberius by name anywhere in the poem. This omissioncan be explained by the assumption that Tiberius, a man intently interested inastrology, was wary of the use of his name in astrological works. I would also suggestthe possibility that Thrasyllus discouraged other astrologers from involvement withTiberius.67 Maranini (1994) 33 discusses the possibility that these lines refer to Germanicusand not to Tiberius. I feel that this is an unlikely interpretation. The passage impliesa lengthy stay while Germanicus is not recorded as having spent much time onRhodes, merely having ‘stopped’ at the island. Also, as I argue, the subsequent linesin the text indicate that this passage does refer to the reigning emperor, not merelyto a possible future emperor.68 With the second grant in A.D. 4 of tribunician power and his adoption by Augustus,Tiberius effectively became the designated successor. From this time on Augustusslowly withdrew from public life leaving more of his duties to Tiberius. After thebanishment of Agrippa Postumus in A.D. 7 Tiberius’ position was unchallenged.69 Steele (1931) 161 uses recturi to place Book Four in the reign of Augustus. Hesuggests that this refers to either Tiberius’ adoption or his assuming the burden ofgovernment in the last years of Augustus’ life.

possible only when the passage is viewed in isolation. If the lines 4.763-77

possible only when the passage is viewed in isolation. If the lines 4.763-77

are considered as one continuous narrative they indicate that the emperor

who had sojourned on Rhodes was now ruling in his own right. As only

Tiberius could be referred to in 4.763–66 (Rhodes and the princeps) he

must be the emperor of Book Four. This interpretation will now be examined.

The first part of this reference states the importance of Libra 4.769–75:

quod potius colat Italiam, si seligat, astrum

quam quod cuncta regit, quod rerum pondera novit,

designat summas et iniquum separat aequo,

tempora quo pendent, coeunt quo noxque diesque?

Hesperiam sua Libra tenet, qua condita Roma

orbis et imperium retinet discrimina rerum,

lancibus et positas gentes tollitque premitque,

This passage demonstrates that Libra was the recognised sign of Rome.

Then in 4.776–7, Manilius describes the actions of the emperor born

under Libra:

qua genitus Caesar melius nunc condidit urbem

et propriis frenat pendentem nutibus orbem.

In 4.776 Manilius is stating that the city has been refounded (and better)

by Caesar. In 4.777 Manilius is stating that the princeps is controlling in

his own individual (propriis) Stoic style the world (pendentem nutibus

orbem). The use of propriis indicates that the emperor was ruling without

a colleague. This clearly refers to Tiberius, who was then ruling in his

own right, not with Augustus. This clearly dates the passage after Augustus’

death.


By this interpretation these three references demonstrate that Tiberius

was the Caesar of Book Four. They describe Manilius’ Stoic interpretation

of Tiberius’ career between his exile in 6 B.C. and his assumption of

office in A.D. 14. In the first passage (4.763–6), the nadir of the princeps’

career is described. He is in exile, his life endangered, but the sign Virgo

and the Sun indicate that this will not be Tiberius’ fate. In the second

passage (4.776–5) Libra is linked with Rome. In doing so Manilius

foreshadows the greatness that awaits the princeps who has that sign. In

the third passage (4.776–7), the career of the ‘Libran’ princeps is followed

to its successful conclusion, the new age of Tiberius in which the City is

rebuilt and the world governed by an astrological and Stoic princeps.70

There is one other reference in Book Four which might refer to a major

figure of Tiberius’ reign and assist in assigning a date: 4.542–6:

Erigone surgens, quae rexit saecula prisca

iustitia rursusque eadem labentia fugit,

alta per imperium tribuit fastigia summum,

rectoremque dabit legum iurisque sacrati

sancta pudicitia divorum templa colentem.

Tiberius’ son Drusus Caesar was born on the 10th of October. If we

assume that Tiberius’ sign was Libra then it is possible that Drusus’ sign,

one month prior to Tiberius’, was correspondingly one sign prior to

Tiberius’, i.e. Virgo. Thus, this reference to Virgo could in turn refer to


70 Suetonius Tib. 69 states that Tiberius was neglectful of the gods as he believed inastrological fate: Circa deos ac religiones neglegentior, quippe addictus mathematicaeplenusque persuasionis cuncta fato agi. Tiberius’ personal philosophical beliefs aredifficult to decipher; Levick (1976) 18 suggests he may have been a Roman ‘amateur’picking and choosing amongst the many offerings of Greek philosophy. She does suggest,however, that Tiberius may have leant towards the Stoic.

Drusus. Levick suggests that Drusus expected a measure of ‘Imperial

Drusus. Levick suggests that Drusus expected a measure of ‘Imperial

power’ after Augustus’ death.71 He had enjoyed a successful career and

his assumption of powers would not be an unreasonable expectation. He

was consul in A.D. 15 and A.D. 21, a general in A.D. 17–20, and received

tribunicia potestas in A.D. 22. One objection to this scenario is that it

discounts the role of Germanicus, Tiberius’ adopted son and possible

successor. This is answered by dating this passage to the period after

A.D. 19, the year of Germanicus’ death. Thus the passage (and Book

Four) were composed after A.D. 19 or possibly after A.D. 22 when Drusus

became Tiberius’ official successor. Manilius could have been describing

Drusus in his role as the successor of Tiberius. This possibility dates


71 Levick (1976) 49–50.

Book Four to the early 20’s, prior to Drusus’ death in A.D. 23.

Book Four to the early 20’s, prior to Drusus’ death in A.D. 23.

1.3.6 Book Five

Before bringing these arguments to a conclusion, it is worth while to

examine Book Five. As discussed in the summary of the Astronomica,

(thesis section 1.2.5 and 1.2.6) Book Five is substantially different from

the earlier four Books, and a case can be made that Book Four was

originally intended as the concluding Book of the work.

This leaves open the question of the date of Book Five as distinct from

the earlier Books. This hypothesis is also suggested by a possible reference

to Sejanus in 5.409–15:

Cumque Fidis magno succedunt sidera mundo

quaesitor scelerum veniet vindexque reorum,

qui commissa suis rimabitur argumentis

in lucemque trahet tacita latitantia fraude.

hinc etiam immitis tortor poenaeque minister

et quisquis verove favet culpamve perodit

proditur atque alto qui iurgia pectore tollat.

If Sejanus is the ‘quaesitor’ of line 5.410, then this dates Book Five to his

period of ascendancy, A.D. 23–31.

There is also reference to the trophies of Pompey that suggests a date in

the 20’s, 5.513, 510, 515.72

hinc Pompeia manent veteris monumenta triumphi

et Mithridateos vultus induta tropaea,


72 Three consecutive lines following the 1985 Goold text.

non exstincta die semperque recentia flammis.

non exstincta die semperque recentia flammis.

The theatre of Pompey was restored by Tiberius in A.D. 22 after it had

been destroyed by fire.73 This passage might refer to that restoration.74

Seneca records that a statue of Sejanus was placed in the newly restored

theatre.75 These two points, the possible references to Sejanus and the

restored theatre, combined with the possibility that Book Five was composed

a significant time after Book Four, suggest that Manilius composed Book

Five in the mid-20's.

1.3.7 Conclusion

To bring these arguments and conjectures to a conclusion, let us summarise

the evidence. The major question in the dating of the Astronomica is the

identity of the emperor of the later Books. The astrological references to

Libra might refer to either Augustus or Tiberius and are thus of no assistance.

The astronomical evidence is too vague to be helpful. What we are left

with are the references to Rhodes, Libra and the emperor in Book Four.

In my interpretation they clearly refer to Tiberius, when he was sole ruler

of the Roman world, after the death of Augustus in August A.D. 14. In

addition the possible references to Drusus and Sejanus push the dates of

the later Books well into the reign of Tiberius.

I suggest that Book One was completed after A.D. 9; Book Two, before

Augustus’ death. Book Three was composed in the period c. A.D. 14,

straddling the reigns of the two emperors. Book Four was the first Book


73 Suet. Tib. 47.74 Steele (1931) 162 suggests other interpretations of this reference: that it mayrefer to the Augustan restoration (32 B.C.) or to the items residing in storagesomewhere other than in the Temple. His main cause for objection is the interval oftime (at least eight years) between the composition of Books Four and Five.75 Seneca Ad Marciam xxii.4.

begun under Tiberius. Perhaps due to the affair of Libo Drusus in A.D. 16

begun under Tiberius. Perhaps due to the affair of Libo Drusus in A.D. 16

and the consequent reaction against astrologers, Manilius may have delayed

the composition of this Book until c. A.D. 20,76 and Book Five may not

have been completed until the mid-20’s.77 This scenario suggests a

composition period stretching over more than fifteen years. While this is

a long time, Manilius saw the Astronomica not merely as a work on

Stoicism or astrology but the culmination of human progress and a guide

to human destiny. Fifteen years is not so long for a work of such complexity

and lofty goals.78

__________________The Sources of the Astronomica 50

76 Tac. Ann., 2.27ff, and Dio 57.15.4f. for details. M. Scribonius Libo Drusus wasbrought to trial on the charge of planning the assassination of Tiberius and his sonsas well as other principes civitatis. He was accused of consulting astrologers whoadvised on his future. Levick (1976) 148-51 discusses this incident.77 Maranini (1994) 50 suggests that this range of dates is broadly accepted. Shedoes mention 33-4 that two schools have emerged as to the final date, one of A.D. 22,the other of A.D. 24. While neither can be disproved I feel that attempting to dateindividual Books to this level of precision is counterproductive and even misleading.78 Virgil required seven years to write the four Books of the Georgics . If we assumethat Manilius had the same degree of poetic productivity then he would have requiredapproximately eleven years to create the Astronomica.

1.4 Sources of the Astronomica

1.4.1 Introduction

Over the next few pages I shall discuss the background material used in

the Astronomica as well as the possible sources Manilius follows. Of

particular interest is the reliance of Manilius on Aratus whose work was

similar in scope to that of Manilius and may have provided an example

for Manilius to follow. This question shall be examined first, then the

other major areas of the poem.

1.4.2 Aratus and his Influence on the Astronomica

1.4.2.1 Introduction

The most prominent popular astronomical author of early antiquity was

the third century Stoic, Aratus of Soli (c. 315–c. 240 B.C.).79 Aratus was

a high-profile figure. He studied Stoicism under Zeno, was an associate

of the Macedonian king Antigonus Gonatas, studied with or knew other

prominent philosophers of the day and published works on medicine and

astronomy.80 His sole extant work, the Phaenomena, is a poetic account

of the astronomical heavens, written for a lay audience. In size, goals and

astronomical information it is similar to Book One of the Astronomica,

and it was allegedly based on the work of Eudoxus of Cnidos. (c. 390–c.


79 On the alleged influence of Aratus see Barton (1995) 48. Clark (1971) 51suggests that Aratus provided the median level of astronomical knowledge for theeducated person. Presumably, Manilius expected his readers to have a greater thanaverage knowledge of this subject. As an alternative measure, the level of astronomicalknowledge in Vitruvius (9.1-6) is greater than that of Manilius and more detailed.80 For a brief biography of Aratus see the introduction to the Loeb Aratus (Mairs195ff.)

340 B.C.).81 It has been suggested that Manilius relied on Aratus’ work as

340 B.C.).81 It has been suggested that Manilius relied on Aratus’ work as

a source of astronomical information.82 As the Phaenomena was used by

others as a source and as it possesses a degree of similarity to the

Astronomica, it is possible that Manilius did base his work upon it. To the

extent that Manilius used Aratus as an authority, he made a good choice.

Aratus explained astronomy in a clear and concise style, and remained a

popular author well into the Roman period, as demonstrated by the

translation of the Phaenomena into Latin by several prominent Romans,

(Cicero, Germanicus and Avienius).83

In addition to Aratus’ popularity, Manilius may have been motivated by

the fact that Aratus was a Stoic, even though there is no evidence of

Aratus’ Stoicism in the Phaenomena, which in fact has a strong secular

theme.84 The Phaenomena contains one reference to indicate Platonic

influence. In lines 456–459 Aratus refers to the

when all planets will align (the

‘Great Platonic Year’).85 There is one factor, however, that may have

deterred Manilius from relying on the Phaenomena, that Aratus’


81 Hipp. Comm. in Arat. 1.2. Cic. Republic 1.14.22.82 Goold (1977) xvi; Mair (1921); Tester (1987) 30–31; Abry, (1994) 179ff.;Dihle (1994) 111; and Hubner (1972) 249. Barton (1995) 48 claims that Maniliussaw himself as a second Aratus, writing a new didactic poem for a new era.83 Ovid Amor. 1.15.6: Cum sole et luna semper Aratus erit, Cic. Rep. 1.14.22: sedpoetica quadam facultate versibus Aratum extulisse. Clarke (1971) 50–2 states theuniversal appeal of the Phaenomena. Erren (1994) 194, 267-73, 280 lists recentwork on Aratus. Maranini (1994) 50-5 discusses the possible influence Germanicusand Manilius may have had on each other. She sensibly concludes that, while they mayhave known of each other, there is no indication of a strong influence.84 While the absence of Stoicism in the Phaenomena argues against its use as a modelby Manilius it is possible that Aratus’ other works and his reputation as a Stoicconfirmed his Stoic credentials. Sikes (1923) 160 puts forward the argument thatAratus was inspired by Stoicism but confined his exposition of Stoicism to prose.85 Plato Timaeus. 39.D. The inclusion of Platonic thought is not surprising. Hahm(1977) 209 strongly argues that both Plato’s and Aristotle’s works formed a sizablecomponent of the basis of the Stoic philosophy.86 Cic. de Div. 2.22.

astronomical source Eudoxus (allegedly) did not believe in astrology.86

astronomical source Eudoxus (allegedly) did not believe in astrology.86

Since it is possible that Manilius did rely upon Aratus the the two works

need to be compared. The areas that will be investigated are: their conceptual

structures, descriptions of constellations, celestial circles, planetary

depictions and religious attitudes.

1.4.2.2 Summary of the Phaenomena

The Phaenomena of Aratus comes to us in three sub-divisions. The first,

and most lengthy is the astronomical section, a ‘sphaera’, approximately

550 lines. The second section, of 180 lines, contains a list of constellations

that rise with each zodiacal constellation. The Phaenomena concludes

with 400 lines of ‘Weather Signs’, a section describing how to predict

weather based on celestial and meteorological phenomena over the course

of the year. This latter section of course has of course no relevance to the

Astronomica.

While there is a similarity of form in their astronomical content the

Astronomica and the Phaenomena, the two works do differ markedly in

their goal. The Astronomica is a work of Stoic astrology in which astronomy

plays a role secondary to astrology. The Phaenomena is a work oriented

towards astronomy, based on the rationality of Greek science with no

mention of astrology or of Stoicism. Indeed, the inclusion of the ‘weather

signs’ in the Phaenomena indicates that its orientation was to events ‘in

the sky’, not merely to the heavens.

1.4.2.3 An Overview of the Two Works


The astronomical section of the Phaenomena begins with a constellation

The astronomical section of the Phaenomena begins with a constellation

catalogue. Aratus divides the constellations into two groups, those found

north and those south of the zodiac. The zodiac is included in the northern

group of constellations, but merely as the divider between the northern

and southern constellations. The northern constellations are listed in order

from the north celestial pole, beginning with the Bears (Ursa Minor and

Ursa Major), moving south-west and including the zodiac and then returning

to the pole sweeping in a westerly direction, concluding with Delphinus.

The catalogue then continues with the constellations south of the zodiac,

beginning with Orion, moving to the more southern constellations, then

westerly, circling the unseen south celestial pole, and concluding with

Procyon (Canis Minor). In total, there are 47 constellations.

After describing the constellations, the Phaenomena briefly mentions the

planets (without naming them), then the celestial circles: the Milky Way,

the tropic of Cancer, the tropic of Capricorn, the celestial equator and,

lastly, the zodiac.

The Astronomica includes the same content, but in greater detail and in a

different format. Manilius divides the constellations into three groups, the

zodiac, the northern, and finally the southern constellations. His description

of the zodiac begins with Aries, the constellation that contains the point

of intersection of the celestial equator and the ecliptic, (the ‘leading’

zodiacal constellation).87 He then continues eastwards along the zodiac.

By listing the zodiac first Manilius indicates the greater importance he

attaches to it. The Astronomica continues by describing the constellations

north of the zodiac, taking as its starting point the north celestial pole and

the constellation Ursa Major. It then moves south-westerly to the zodiac

and then easterly, concluding with Heniochus (Auriga). The southern


87 See Appendix A for a full description of the ‘First Point of Aries’.

constellations begin with Orion and then move south, circling the south

constellations begin with Orion and then move south, circling the south

celestial pole in an easterly direction, concluding with Flumina (Eridanus);

a total of 44 constellations.

Manilius then mentions the planets and the celestial circles: the arctic

circle, the tropic of Cancer, the celestial equator, the tropic of Capricorn,

the antarctic circle, the equinoctal colure, the solstitial colure, the meridian,

the horizon, the zodiac and the Milky Way. The Astronomica then concludes


Book One with a lengthy description of comets.

Book One with a lengthy description of comets.

Table 1

Comparison of the order of the constellations in the Phaenomena and the

Astronomica .

Aratus Manilius

zodiacal constellations:

easterly

northern constellations: northern constellations:

westerly easterly

southern constellations: southern constellations:

westerly easterly


Table 2

List of Celestial Circles in the Astronomica and Phaenomena

Astronomica Phaenomena

the arctic circle

the tropic of Cancer the tropic of Cancer

the celestial equator the celestial equator

the tropic of Capricorn the tropic of Capricorn

the antarctic circle

the equinoctal colure

the solstitial colure

the meridian

the horizon

the zodiac the zodiac

the Milky Way the Milky Way


Aratus’s constellations are listed in a westerly order, possibly following

the daily path of the Sun and stars in the sky. Manilius describes his

constellations in the opposite order, easterly, possibly basing his

presentation on the direction the sun, moon and planets take over the

course of a year. In this aspect may be seen a fundamental difference

between a non-astrological work, that of Aratus, and an astrological

work, that of Manilius.

Manilius also goes into more detail than Aratus in his description of the

astronomical circles, and adds to Aratus’ list the arctic and antarctic

circles, the colures, the meridian and the horizon.88 The Astronomica also

lists the circles in a different order from the Phaenomena, and discusses

comets, meteors, different theories as to the origin of the universe, and

the Moon (Astronomica 1.809–926). These topics are not covered in the

Phaenomena (where the Moon is discussed in the meteorological

‘weather signs’ section but not in the astronomical section).

In sum, there is a general similarity in the basic structure of the two

works. The size of their astronomical sections are approximately 500

lines each and they discuss largely the same topics in near the same order.

Beyond this basic similarity the two works differ widely in detail, with

the Astronomica providing substantially more information.

1.4.2.4 An Examination of the Individual Constellations

of the Phaenomena and the Astronomica

Both authors describe the navigational attributes of the Bears (Phaen.


88 These astronomical circles are explained in Appendix A.

351-444, Astron.1.294-304) Ursa Major and Ursa Minor, both of which

351-444, Astron.1.294-304) Ursa Major and Ursa Minor, both of which

lie near the north celestial pole. In the modern era, Alpha Ursa Minor

(Polaris, the Pole star) is less than a degree from the north celestial pole,

providing a sure and easy means for identifying due north. In antiquity,

the north celestial pole was not found close to a bright star. It lay between

the constellations of Draco and Ursa Minor. The closest bright star was

Beta Ursa Minor (2nd magnitude), approximately 8 degrees from the

pole. The neighbouring constellation and mythological relative, the

brighter and larger constellation of Ursa Major, was further from the

north celestial pole (20 degrees). A navigator in antiquity, by locating

Ursa Minor, would find a reasonably accurate identifier of true north.

Conversely, locating Ursa Major, while a somewhat easier task (more so

around the time of the full Moon when the Moon’s brightness would dim

the light of the single bright star in Ursa Minor) would be a less sure

guide to true north.

In both the Phaenomena and the Astronomica Greek sailors are said to

use Helice (Ursa Major), the brighter, but less accurate constellation, as a

guide to north, while both works claimed that the Phoenicians used the

more accurate but fainter Cynosura (Ursa Minor). However, Manilius

refers to the Phoenicians by the term, Poeni, while Aratus uses the term

‘Sidonian’. Aratus includes mythological lore with his description,

whereas Manilius does not. Similarities exist in both accounts but this

usage of the Bears must have been common knowledge in the ancient

world. It does not necessarily indicate a linkage between Aratus and

Manilius.

Aratus makes particular mention of a star in Virgo - Epsilon Virgo, (Phaen.


137–40):89

137–40):89

Its name, ‘associated with the vintage’, may have been derived from its

heliacal rising occurring at the beginning of the grape-gathering season.90

Manilius, however, does not mention this star, probably due to its low

brightness. This suggests that Manilius was not following Aratus in this

instance.

Hydor

In lines 395–8 Aratus refers to a minor constellation in the far southern

sky, which he names Hydor (Water). This constellation (which does not

exist today) and the area of sky are not described by Manilius. It may

have been a creation of Aratus, since the constellation is mentioned nowhere

else. The two stars forming the constellation may be Alpha and either

Beta or Gamma Phoenix.

Bestia (Lupus)

The constellation Lupus is small, far southern and faint. It is correctly

referred to and located by Aratus, Phaen. 441–442:


89 Mair’s (1921) Loeb edition 216 refers to line 138 as being suspect, renderingany conclusion on this matter questionable.90 Liddel & Scot (1940) s.v. , Burnham (1978) 2069. Vitruvius refersto this star giving it this title, Vit. de Arc. 9.4.1.

Manilius does not refer to this constellation, although Goold hypothesises

that he confused it with the Cetus.91

Corona Australis

The constellation Corona Australis is small, far southern and faint. It is

briefly referred to by Aratus but not mentioned by Manilius, Phaenomena

399–401

Eridanus

Both Aratus and Manilius include the large constellation Eridanus in their

catalogues, but Manilius refers simply to ‘Flumina’ (1.440), while Aratus,

in line 360, refers to it as ‘Eridanus’.92 The two poets differ in description

of Eridanus. For Aratus the constellation begins at the foot of Orion and

ends in Cetus (359-66). For Manilius the constellation also begins at

Orion’s foot but intersects with a stream of water from Aquarius in the

constellation Piscis Notius (1.438-42). He refers to them as ‘two rivers’.

He does not make mention of Cetus. The two accounts clearly reflect

different origins.

Delphinus

Both works give the constellation Delphinus only four stars (Phaen. 316-8,

Astron. 5.713). Delphinus comprises five bright stars, not four. As Aratus

says, there are two pairs, side by side. There is also, however, a fifth star

(Epsilon Delphinus), as bright as the third brightest star of the two pairs

(Gamma Delphinus-3rd magnitude), lying 3 degrees to the south. Neither

Aratus nor Manilius mentions this star. It is possible, therefore, that Manilius


91 Goold (1977) xxx–xxxi, Mair (1921) 241 n. f.92 Mair (1921) 234, n. e, states that Aratus was the first to use the name Eridanusfor the constellation.

was following Aratus in this instance, or it could mean that this star was

was following Aratus in this instance, or it could mean that this star was

not included in any ancient constellation. Although Ptolemy in his more

extensive catalogue of Northern Constellations, Almagest Book Eight,

includes ten stars in Delphinus including Epsilon Delphinus, it is possible,

that stars not in the central four were not included in the popular constellation

definition of Delphinus.

A major different between the two poets is found in their view of the

origin of constellations. Aratus (Phaen. 367-85) informs his readers that

the men of old formed the constellations out of those brighter stars which

had an order or pattern. This criterion left a number of ‘ungrouped’ stars

(catasterisms) which are not part of any constellation. The passage also

states that the constellations were formed by humans (Phaen. 371-3).

Manilius, (Astron. 456-73) taking the view of Stoic predetermination,

describes the constellations without mention of catasterisms, nor are any

such listed in his catalogue. He also credits the formation of the

constellations to natura, and not to any human activity (Astron. 463-4).

This is one clear conceptual difference between the two works.93

1.4.2.5 An Examination of Religion in the Two Works

Both the Phaenomena and the Astronomica include references to the

traditional gods, but they differ markedly in attitudes to them. To Aratus,

Zeus is the King of the Gods and a major influence on human affairs

(principally expressed in the introductory lines at Phaenomena 1–18).

Zeus is described as the creator and prime source of the universe. This

attitude continues through the Phaenomena where Zeus and the gods are

given a central role.


93 Montanari (1993) 56-7., Kidd (1967).

In the Astronomica Manilius states clearly that Jupiter plays a lesser role

in the universe than the Stoic God. In Astronomica 1.66–112, Manilius

traces the development of humanity, during the progression of which the

central importance of Jupiter gives way to Stoic reason. This is specifically

dealt with in lines 1.103–5:

...solvitque animis miracula rerum

eripuitque Iovi fulmen viresque tonandi

et sonitum ventis concessit, nubibus ignem.

This should not be considered as disbelief in the gods.94 Manilius still

grants the traditional gods respect. Jupiter plays his part in traditional

religious beliefs, but in general the gods give way to Stoic fate. This is

best described in 1.905–10, where human beings investigate the gods and

then continue past them to a knowledge of astrology:

saepe domi culpa est: nescimus credere caelo.

civilis etiam motus cognataque bella

significant. nec plura alias incendia mundus

sustinuit, quam cum ducibus iurata cruentis

arma Philippeos implerunt agmine campos


94 In the Astronomica Manilius clearly views the traditional gods as near irrelevantto his Stoic universe. This raises the possibility that Manilius did not believe in thegods and merely included them in the poem due to poetic and political motives. Oneother rationale for inclusion is found in the Derveni papyrus. This is a fourthcentury B.C. Macedonian cremation scroll. The papyrus contains both an account ofthe traditional gods (Zeus, Rhea etc.) and a Presocratic cosmogony where a sole godcreates the universe and the original elements. These two seemingly contradictoryaccounts are presented with no perceived concern for their incompatibility. Theclassicist G. Most (1997) 122 argues that ‘they are both true’ - but not in the sameway. At work is a religious form of ‘doublethink’. This text suggests that it waspossible to reconcile traditional beliefs and the cosmology of Greek science. PossiblyManilius was working in this tradition.

Aratus and Manilius also possessed different views of human history.

Manilius depicted, at some length, his version of human prehistory

(1.66–112). He saw human cultural evolution as a gradual and difficult

rise from ignorance and primitive lifestyle to the contemporary world of

navigation, agriculture and above all, astrology. Aratus puts forward an

opposing history of human society. The Phaenomena (96–136) tells us

the story of the Golden and Silver Ages (similar to Hesiod), and lastly of

the Age of Bronze. From Aratus we learn that the human condition grew

worse with time, not better, since human beings had originally lived in an

idyllic world where the gods (or at least Virgo/Justice) lived among men,

but then men had moved to a more violent world with the invention of

bronze and swords. These differing accounts of human development reflect

very different outlooks on the world.

1.4.2.6 References in the Astronomica to the Phaenomena

There are three passages in the Astronomica which possibly derive from

the Phaenomena. In Astronomica 1.401–3 Mt. Taurus is referred to as an

observation point for the heliacal rising of Sirius. Goold suggests that this

reference was a compliment to Aratus, who was a Cilician.95

hanc qui surgentem, primo cum redditur ortu,

montis ab excelso speculantur vertice Tauri,

eventus frugum varios et tempora discunt,

This explanation is possible, but there are other explanations, the most

likely of which is that Manilius was referring to a city in the region that


95 Goold (1977) 37 n. a. Manilius twice refers to Mt. Taurus in Book Four 623,675.

was prominent in the world of astrology. Cicero states that the city of

was prominent in the world of astrology. Cicero states that the city of

Telmessus in Caria was noted for its interest in astrology (de Div. 1.91),

which lies on the border of the Taurus range of mountains.

In a later passage, where Manilius places himself in a line of authors

beginning with Homer, he makes a reference to other unnamed authors.

Goold believes Aratus is included in this list 2.25–7.96

astrorum quidam varias dixere figuras,

signaque diffuso passim labentia caelo

in proprium cuiusque genus causasque tulere;

This interpretation may be correct, and indeed, it would be surprising if

Manilius did not make some acknowledgement of Aratus, yet this is only

a minor reference and one made indirectly. By itself, it suggests that

Aratus did not have a strong influence on Manilius.

The last reference is a curious passage referring to the relative size of the

universe. Aratus (Phaen. 541–3) tells us that the distance from the Earth

to the celestial sphere is one sixth the circumference of the sphere. Manilius

gives us the same information but goes into more detail and greater

length (1.539–56). The only significant difference between the two accounts

is Manilius’ correct statement that Pi is slightly greater than three, a fact

not mentioned by Aratus. It is difficult to reach a conclusion as to the

worth of this last point. It has little real relevance to the text of either

work. It is, however, the clearest example of a specific similarity between


96 Goold (1977) 85 n. g.

the two.

the two.

1.4.2.7 Conclusion to Aratus

The astronomical sections of both works are similar, in that each provides

a descriptive account of the heavens of approximately the same length,

but beyond this there is little similarity.

The Astronomica is Stoic and astrological, where the Phaenomena, in its

astronomical section, takes a more secular approach. They differ in historical

orientation: the Phaenomena postulates a Golden Age, while the

Astronomica views the past as a painful struggle. The Phaenomena reveres

the gods, while the Astronomica displaces them in favour of Stoicism.

The two works differ in the layout, presentation and detail of their

constellation catalogues. The major difference, however, is their differing

accounts of astronomical knowledge. The Astronomica presents more

extensive and detailed information with regard to the planets and the

celestial circles, and, having had an additional two centuries of astronomical

progress to draw upon, Manilius seems to have made use of this new


knowledge.

knowledge.

1.4.3 Manilius’ Stoic Sources

Since it is clear that Manilius made little use of the Phaenomena as a

source, we should consider what other possible sources he used. From the

text it is clear that the poet follows the Stoic creed. His major departure

from pre-existing Stoicism is his subordination of all of its other aspects

to astrology. In this it is possible to detect a logical line of development

from early Stoicism. If fate does rule all and assuming that God does

grant human beings a measure of significance in the universe, then a

means of determining fate should exist.97 The question is, who did develop

astrology to the central place it enjoys in the Astronomica? Was it Manilius

or an earlier Stoic?

It is possible that Manilius rewrote, and even perhaps carried forward the

integration of Stoicism and astronomy and added his own perception to

the field of Stoic astrology. It should be noted that Manilius was the first

Roman Stoic astrologer of note, and that his work was written for a

Roman audience. In this area, if nowhere else, Manilius should be considered

an original figure in Stoicism. Much of the integration of astrology and

Stoicism is credited to Posidonius who may have been a significant source

for the Astronomica.98 In particular, Panaetius and Posidonius adapted

Stoicism to support the Roman State. Manilius does clearly follow this

model.99 There are two specific sections of his Stoic thought that can be

attributed to other Stoics. The cosmological model used in the Astronomica


97 Cic. de div. 1.82-3, see Long & Sedley 264-5 for a discussion of this point.98 Sikes (1923) 174.99 This point is discussed by Francis (1995) 4ff. Francis suggests that Panaetiuswas the first Stoic figure to use Stoicism to support the Roman State. Erskine (1990)192ff. suggests that Posidonius not only continued Panaetius’ Stoic support of Romebut added to it. This is a cause for considering Panaetius and Posidonius as sources forManilius.

(1.149–72 et al.) is identical with the model attributed to Chrysippus.100

(1.149–72 et al.) is identical with the model attributed to Chrysippus.100

Also, many Stoics believed in a universe of periodic renewal in which

fire first destroys and then recreates the cosmos,101 but Manilius does not

state this view, and in fact he suggests the opposite. In this he was

following in the footsteps of four divergent Stoic figures: Zeno of Tarsus,

Diogenes of Babylon, Boethus of Sidon and Panaetius,102 who disagreed

with the mainstream view of the universe and suggested that the universe

was fixed.

From this brief consideration of Manilius’ Stoic beliefs, it is clear that he

used a range of possible sources and that he modified their beliefs to suit


100 Hahm (1977) 57ff reconstructs Chrysippus’ cosmology.101 Manilius does not mention this aspect of cosmology in his major description ofStoic cosmology (1.149–72), nor does he discuss the ultimate fate of the universe inany detail elsewhere.102 Cicero de Div. 2.85–97 and Diog. Laer. 7.142, cf. Sandbach (1975) 79.

himself and his audience.

himself and his audience.

1.4.4 Manilius’ Astrological Sources

The second major concern of Manilius’ work was astrology, and it comprises

the single largest section of the Astronomica. In composing this presentation

Manilius clearly called upon a wide variety of sources. In the astrological

Books (Two–Five), there are four major astrological theories detailed,

each different from the others, with each presented with a number of

variants. Each Book also contains snippets of other astrological theories.

The identifying theme of all of these is their reliance on the zodiac and

not the planets as major source of prediction. Manilius evidently chose to

relegate the planets to a secondary role in his astrological beliefs.

Very little is known of the history of astrology. The presence of these

different astrological theories suggests that there were different ‘schools’

of astrology which Manilius freely used. It is also possible to deduce,

from the evidence in the Astronomica, that there was a major division of

astrology into that based upon the zodiac and that upon the planets.103 This

former category is further divided into at least the four major divisions

recorded by Manilius.

There is, however, a source for one procedure. In Book Three Manilius

presents seven formulae that describe how to calculate the sign of the

zodiac rising at a particular time. The details of these formulae suggest a

Babylonian origin. This in turn suggests a reliance of astrology upon

earlier and simpler formulae (discussed in Chapter Six).


103 This differs from most other astrologers who gave the planets a higher degree ofastrological importance. Ptolemy Tet. 2.8.55ff outlines the central importance of theplanets in his astrology. Sextus Empiricus Ad. Ast. 5 lists their significance, inparticular, and throughout his entire critique of astrology.

One significant astrological feature in the Astronomica is the use of the

One significant astrological feature in the Astronomica is the use of the

Hipparchian (mid-second century) astronomical magnitude system in an

astrologically adapted form (5.710–7). The author of this adaptation is

unknown but its existence provides a strong argument for the reliance of

Greek and Roman astrology on astronomy. This passage suggests that

there was a significant body of astrological literature extant in Manilius’

time, little of which has survived. The importance of these lines is discussed

in thesis section 3.6.

1.4.5 Manilius’ Astronomical Sources

The astronomical sources of the Astronomica were as varied as the

astrological. In the Sphaera of Book One Manilius takes cognisance of

several different sources. In the account of the celestial circles, two

indications of source material emerge (1.539-804). In a unique reference

in the Astronomica, a sexagesimal degree system is used to delineate the

separation of the various circles. Elsewhere, for other purposes, a 360

degree system is used (e.g. Book Three’s horoscope formulae), which

suggests a source in the era of Eudoxus or later. There is also the number

of circles in the text, a full set of eleven, which suggests a date from the

mid-fourth century (cf. thesis section 3.3). In the last lines of Book One

the poet provides a garbled account of meteors and comets (1.809-926).

The style of this section is markedly different from that of the celestial

circles. It is in a ‘mythical’ style while the circles are described in a

‘scientific’ manner.

There is one negative piece of information that guides us to Manilius’

sources. He denies the existence of the ‘Precession of the Equinoxes’ (the

slow and continual movement of the stars around their fundamental


reference points). This was a discovery made by the astronomer Hipparchus,

reference points). This was a discovery made by the astronomer Hipparchus,

but Manilius, writing over a century after Hipparchus, refers to the stars

as being fixed (1.275–84). This suggests that Manilius was not interested

in the mathematical science of astronomy nor in the complexities that

contradicted his own view of the heavens. Manilius probably relied on

‘popular’ publications on astronomy.

Book Three is an almost exclusive discussion (3.43–509) of astrological

procedures which originate from Babylonian sources (discussed in full in

chapter Six). These procedures are clearly different from those found in

the other astrological Books. In a similar fashion the paranatellonta of

Book Five (5.32–709) is a simpler form of astrology than found in the

other astrological Books. This, once again, suggests a Babylonian origin.

The Planets are one astronomical topic in which Manilius displays even

less than average interest, and he merely lists the five visible planets and

the Sun and Moon in correct sidereal order (the length of their orbit

around the Sun). All that can be said is that this reflects a source later

than the fourth century when a clear understanding of planetary sidereal

order emerged in the Greek world

There are a number of minor references to sources that confirm the wide

range of works consulted by Manilius. In 1.539-56 the poet makes a

passing reference to Euclid’s geometry (cf. thesis section 3.2.2). In 1.408

there is a possible reference to Aristarchus (cf. thesis section 3.2.4). In his

constellation catalogue (1.255-531) Manilius omits several minor

constellations not created till later than the 3rd century B.C. (cf. thesis

section 3.4.3)


Last within the topic of the sources for Manilius’ astronomy is the colour

Last within the topic of the sources for Manilius’ astronomy is the colour

of the star Sirius. A number of ancient authors (Homer, Cicero, Seneca

and Ptolemy) refer to the star Sirius as being red in colour. In the modern

world Sirius is blue/white, and, according to stellar theory, this should

have been its colour 2,000 years ago. In the Astronomica Manilius states

that Sirius’ colour is blue/white. This suggests the possibility that the

other authors were incorrect and that Manilius preserves the correct

tradition. This indicates that he did produce some of his own observations

(see Chapter Four for a discussion of this question).

1.4.6 Conclusion

It is clear that Manilius did not rely on a single source for his poem. He

had at his fingertips a wide variety of material from the ancient world that

he examined, selected and modified to suit his goals. He relied upon a

smorgasbord of sources, which, with the exception of those on Stoicism,

he assembled into one work with little attempt at reconciliation. This

demonstrates that Manilius was, to a large extent, original in his own

work. He used the material of earlier authors but he constructed his own

version of Stoicism.

______________________A History of Astronomy and Astrology 72

2. Chapter Two: Manilius and His Intellectual

Environment

2.1 A History of Astronomy & Astrology104

2.1.1 Introduction

My purpose here is to provide an overview of the development of astronomy

and astrology in the Greek and Roman world. This will assist in placing

the Astronomica in its cultural milieu as well as providing a basis for an

investigation of Manilius’ views. The two subjects, astronomy and

astrology, share a closely related history in terms of the range of theories

as to their origins, primacy and rates of development. I take the view that

the Greek science of mathematical astronomy was based upon a pre-existing

body of Babylonian astrological knowledge,105 and that Greek and Roman

astrology, such as is found in the Astronomica, was in turn, built upon a

combination of Babylonian astrology and Greek astronomy.

2.1.2 The Astronomy of the Greeks

The Greeks began their investigation of the heavens with at least some of

the astronomical knowledge of Mesopotamia and Egypt.106 They used

that knowledge and their own research to create a theoretical basis for

astronomy over the course of classical civilisation.


104 A number of astronomical terms are used in this section. They are defined inAppendix A.105 Dicks (1970) discusses this assumption in chapter 2, ‘Homer and Hesiod’ as wellas specific examples e.g. 146.

The Greek poets Homer and Hesiod were the first to incorporate

astronomical material in their works. In Iliad 18.483–9 Homer describes

the heavens depicted on Achilles’ shield. The Earth is surrounded by

water with the stars supported by pillars, several stars and constellations

are named (Sirius, Pleiades and others). Homer makes no suggestion that

the heavens as such controlled human destiny, which is left to the gods

and fate.

Hesiod’s Works and Days is a didactic treatise on farming which makes

use of astronomical phenomena to guide the farmer in the agricultural

activities required over the course of the year.107 A slightly higher level of

astronomical knowledge is found in the Works and Days than in Homer,108

which may reflect nothing more than the different goals of the two works.

Hesiod includes no suggestion of astrology, nor does he discuss the the

divinity of the heavens, nor offer a theoretical basis for astronomy. Astrology

seems not to have been a potent force in this period.

The first stage of Greek scientific research into the heavens is believed to

have been carried out in Ionia and southern Italy in the sixth century B.C.

by a number of Greek philosophers known as the pre-Socratics.

Unfortunately, little hard evidence exists of their work. The first of these

philosophers were Thales,109 Anaximander and Anaximenes. The little


106 There is sufficient evidence to posit the fact of Babylonian influence, but, thedetails of this influence, its date and ultimate importance to the origins of Greekastronomy is unclear. Barton (1994-2) 21 summarises two pieces of evidence;first, that Hesiod includes Babylonian myths in his Theogony and second, that theattempt to reform the calendar of Athens in 432 B.C. relied on Babylonian methods.Neugebauer (1975) 589–614 lists other possible influences of Babylonian astronomyon its Greek counterpart: the sexagesimal system, time reckoning, a 360 degreecircle, the zodiac and numerical parameters (e.g. 30 degrees per zodiac constellation).107 Pannekoek (1961) 95.108 Dicks (1970) 34.

that can be gleaned about this period from the extant sources reveals only

that can be gleaned about this period from the extant sources reveals only

a basic level of astronomical knowledge.110 The major achievement of

this period was the continuation of the belief in a ‘secular’ heaven in

which rational explanations for celestial phenomena are explored. In this

pre-Socratic era there was still no hint of astrology, and while the heavenly

bodies themselves may have been considered divine, individuals such as

Anaxagoras challenged even this belief by stating that the Sun and Moon

were not gods but merely stones.111


109 According to Dicks (1966) 37, the story by Herodotus (9.74.2) that Thalespredicted a solar eclipse (585 B.C.) is false. He bases his argument on the fact thatthe prediction of the occurrence and even more so the path of visibility of a solareclipse are the most difficult of astronomical calculations. He believes that the levelof astronomical knowledge at that time was woefully inadequate in its dealing withcelestial mechanics and that it was not until the time of Hipparchus that such acalculation could have been reliably made. The opposite case, that it would have beenpossible for Thales to have predicted the eclipse is made by Russell 44 and assumesthat Thales relied upon Babylonian deduction of repetitive patterns of eclipses. Theanswer to this question probably lies between the two extremes. Thales may havelearnt of Babylonian solar eclipse observations via Lydia. He then reexamined theevidence and made a number of predictions. One of these predictions came true thusgranting him his reputation as an eclipse predictor.110 A summary of the major figures and their credited theories follows:Thales of Miletus (c. 624–c. 547 B.C.), one of the ‘wise men’ of Greece. He consideredthat water was the first principle and that the Earth was a flat disk which floated onthe water. Anaximander (c. 611–c. 546 B.C.) posited a cylindrical Earth floating inspace. Anaximenes (c. 585–c. 526 B.C.) had a universe with the Earth and the Sunand Moon shaped as a flat disks, on which the stars floated. Xenophanes (c. 570–c.480 B.C.) believed that the Sun formed anew each day. Pythagoras (c. 580–c. 500B.C.) founded the Pythagorean school, created a spherical Earth, knew of the obliquityof the equinox and the path of planets. Heraclitus of Ephesus (c 500 B.C.) believedthat the Sun was a burning mass that was renewed and extinguished each day. Anaxagorasof Clazomenae (c. 500–c. 428 ) believed that the celestial bodies were not divine,that the moon shone by the Sun’s light and saw the Earth as a cylinder. Empedocles ofAgrigentum (c. 494–c. 434 B.C.) was the developer of the belief in four elements.111 Diog. Laer. 2.11–2. Diogenes Laertius was a third Century A.D. compiler of Greekphilosophies and philosophers. His work, while late, does contain a great deal ofmaterial. Book Two is the principal source for the biography of Anaxagoras. Diogenespreserves several accounts of Anaxagoras’ actions and beliefs, and suggests thatAnaxagoras saw a meteor fall to Earth, which led him to develop a theory that thecelestial bodies were all merely physical and that the Sun was composed of glowingiron.

By the end of this period the beginnings of scientific astronomy had

developed: the geo-centric model of the universe and a belief in an initial

element, fire, from which the other elements originated.112 What is not

found by the end of the pre-Socratic period is the use of detailed

observational evidence nor of mathematics to analyse the heavens.113

2.1.3 The Fourth Century

A turning point in Greek astronomy was reached in the fourth century

when the knowledge of the previous period was combined with a coherent

mathematical basis. The century begins with a clearer understanding of

astronomy. Plato, even though he was not an astronomer, discussed

astronomy in his philosophical works, giving us the earliest comprehensive

and datable account of Greek astronomy. He affirmed that the universe

was geo-centric in nature.114 Aristotle continued the discussion. His works,

while not primarily astronomical, contain a great deal of background

information derived primarily from Plato, thus also founded upon a

spherical, geo-centric universe.115


112 Dicks (1970) 39–61 and Samuel (1972) 25 discuss fifth-century Greek astronomyand conclude that, by the end of the fifth century, the geo-centric model of theuniverse was fully accepted.113 The level of astronomical knowledge in this period is a matter of some dispute.Dicks (1966) argues that a rigorous form of mathematical astronomy did not occuruntil as late as the Hellenistic period. The alternative view is that, while it is correctthat scientific astronomy did not exist until later in Greek history, it is possible thatan intuitive form of astronomy, in which concepts are understood not by mathematicsbut by speculation, existed at an earlier date. This latter view is championed by Kahn(1970).114 Plato was not overly concerned with astronomy, nor with the physical sciences,yet his works do contain references to astronomical concepts. These are found in theTimaeus 30–39 and the Republic 529. In this latter work Plato stated that astronomersshould not concern themselves with the visible universe but seek the true mathematicalnature behind it.

The astronomer who gave this model its mathematical basis was Eudoxus

The astronomer who gave this model its mathematical basis was Eudoxus

of Cnidus (c. 390–340 B.C.). He created the first mathematical model of

planetary motion, which changed astronomy from a descriptive field into

the beginnings of a rigorous science. The model Eudoxus designed had

the stars and planets attached to and rotating upon spheres.116 While this

concept was mathematically valid, it clearly did not place great importance

on observational evidence, and it could not accurately predict planetary

motion. Irrespective of its faults, the ‘scientific astronomy’ of the ancient

world had begun.

2.1.4 The Hellenistic Period

The conquests of Alexander exposed Greek science to the accumulated

observational data and traditions of the Babylonians. This provided an

impetus to Greek science, which made great strides in all fields between

the time of Alexander and the Roman conquest. The earliest astronomical

and mathematical figure of this period was Aristarchus of Samos (c.

310–230 B.C.), who apparently published several major works on

astronomy, of which only one survives: On the Sizes and Distances of the

Sun and Moon. His major achievement was to suggest a helio-centric

universe with the Earth, the planets and the stars circling the Sun. This

innovative hypothesis was not generally accepted and was only rarely


115 Aristotle’s major contribution to astronomy was not his astronomical publicationsbut his creation of a ‘scientific method’. His formalisation of logic and its use provideda basis for rigorous analysis of astronomical data by his successors. See Schenk342–59. Aristotle’s ‘astronomical’ works include de Caelo (primarily Book Two),and Metaphysics, Book Eight.116 The ever-changing path of the planets was explained by the continuous movementof planets between different spheres. This model is preserved in two works, inAristotle’s own Metaphysics l 8, and in a longer version by Simplicius’ Comm. on deCaelo. 492.31ff. Pannekoek (1961) 109 provides a modern summary of this system;cf. Neugebauer (1975) 675–89.117 Seneca NQ. 7.2.3. Thomas (1971) 2-5, Loeb translation discusses this point. Alsosee Heath (1921) for a detailed discussion of Aristarchus and his work.

mentioned in later literature.117

mentioned in later literature.117

Another major figure of this period was Eratosthenes of Samos (c. 275–194

B.C.), head of the Alexandrian Library and author of a number of texts on

a wide range of topics. His major astronomical achievement was the

determination of the size of the Earth and a measurement of the obliquity

of the equinox.118 In this, he continued the tradition of Eudoxus in relying

on mathematics to analyse phenomena.

The greatest astronomer of antiquity was Hipparchus of Samos (c. 190–126

B.C.), whose most important discovery was the ‘precession of the

equinoxes’. He is also credited (based largely upon evidence in Ptolemy’s

Almagest119) with: creating the first positional stellar catalogue, improving

the epicycle theory of planetary motion, proposing a theory of the motion

of the Sun, Moon and Earth system and incorporating the astronomical

observations of the Babylonians into his research.

The last prominent astronomer of antiquity was Ptolemy Claudius

(mid–second century A.D.). He wrote thirteen books on astronomy known

collectively as the Almagest which work was preserved in the Medieval

and Arabic worlds and was considered the definitive text on astronomy.

The Almagest includes virtually all of the astronomical knowledge of the

ancient world, containing sections on: planetary motion, the Sun, Moon

and Planets, eclipses, instruments, calculations for the rising and setting

of stars and a stellar catalogue. There is some debate as to whether Ptolemy’s

work is original scholarship which incorporates some observations by

earlier astronomers, or whether it is a plagiarised account of the work of

earlier astronomers.120 Irrespective of the answer to this question, the


118 Neugebauer (1975) 660, 304f., 734.119 Alm. 7.3.

Almagest is the major source of classical astronomical knowledge. Unlike

Almagest is the major source of classical astronomical knowledge. Unlike

earlier Greek astronomers Ptolemy was interested in astrology. This passion

prompted him to write the Tetrabiblos, a four-book work on astrology,

the opening lines of which suggest that he considered the Almagest as a

mere introduction to this work. This, in turn, suggests that Ptolemy

considered himself more an astrologer than an astronomer.

2.1.5 The Astrology of the Greeks and Romans

There is no evidence for astrological belief in Greece prior to Alexander.

There was always a perception that the celestial bodies were divine, but

this did not translate into a belief that they affected the Earth.121 This

situation changed, however, after contact with the east, and a concept

emerged of a form of sympathy between the heavens and the Earth.122

This was seized upon by the Stoics in the third century (or possibly later)

who made it a major part of their doctrine.123

The degree to which Babylonian astrology influenced the Greek’s is a

matter of debate. It is certain that at least part of Babylonian sky-lore was

incorporated into the Western tradition, but only a few names and a small


120 Ptolemy’s position in the history of Astronomy is unclear. The belief that Ptolemyfabricated his observations is discussed in the work of the astrophysicist RobertNewton (1977). The alternative view, that Ptolemy was a researcher of high standardsand originality, is also held and promulgated by a number of authors. An excellentarticle that argues this case is by Riley (1995) 221–50.121 Neugebauer (1975) 202-3 suggests that astrology did not gain prominence in theGreek world until c. 200 B.C.122 Cicero records that Eudoxus strongly criticised astrology and Babylonian astrologers(de Div. 2.87).123 The belief that astrology was rapidly incorporated into Stoicism is argued by Sikes(1923) 173 who states that Stoicism was ‘easy prey’ to the influence of astrologyand suggests an early adoption by the Stoics of astrological doctrine. Cumont (1912)40–1 also suggests that Stoicism rapidly adopted Babylonian astrology into itsphilosophy. Barton (1994-1) 34 & 37 counters this view and argues that only inthe middle of the second century was there strong Stoic interest in astrology.

number of fragments have been associated with this transmission,124 so

number of fragments have been associated with this transmission,124 so

there is insufficient evidence to draw-up a history of this process.

Essentially, less is known of astrology than of astronomy in the period

after Alexander. This may be attributed to the innate secrecy of astrological

procedures and the reservations the Greeks seem to have had concerning

this field. Only in the Roman period does a clearer picture of astrological

doctrine emerge.125

Astrology seems to have been introduced into Italy by the Greeks in the

second century B.C.126 Presumably it centred on Rome because of the

increasing interest of upper-class Romans in Greek culture and the

increasing number of Greeks who came to Rome as captives and teachers.127

The first prominent Roman astrologers of whom we possess definite

knowledge were Tarutius of Firmium and Publius Nigidius Figulus, both

contemporaries of Cicero.128 From this we can conclude that Roman

astrology did not come into its own until the first century B.C.


124 Democritus of Abdera third century B.C., Berossus of Cos first century B.C.,Sudines of Babylon first century B.C. Barton (1994) chapter Two examines thisperiod of astrological history.125 Barton (1994-1) 30–1.126 The beginnings of Roman astrology can be dated to the late third century when theauthor Ennius referred to astrologi (cf. Cic. de Re Publica, 1.18.30). A reference byCato the Censor suggests that astrology was prevalent at some levels of society in themid-second century, since he advised that an overseer should not consult an astrologer(de Agri Cultura 1.5.4). Valerius Maximus (1.3.3) recounts the first expulsion ofastrologers from Rome in 139 B.C. These were probably non-Romans who practisedin Rome.127 Shackleton Bailey (1979) offers an alternative translation and meaning to Goold’sinterpretation of 1.512, fatis Asiae iam Graecia pressa est. Goold ad loc. suggests thatthis merely means that Greece had been displaced as the ruler of the world, as Asiahad been. Shackleton Bailey’s interpretation places greater emphasis on Rome’s destiny.First Asia (Babylonia) gained primacy in astrology, then Asia gave way to Greece,and now Rome in turn takes over the mantle of astrology from Greece. As Maniliuscarries the flame of astrology to Rome, he places his work at the centre of Romansocial thought and progress. Shackleton Bailey’s translation seems more in sympathywith Manilius’ underlying argument.128 Suet. Aug. 94.5, cf. Barton (1994) 37.

The development of astrology is a long and largely unknown process.129

Until the time of Augustus we possess no definite record as to the details

of astrological formulae. It is certain that astrology was popular in the

Imperial period, with all classes of society using it and other forms of

divination to foretell the future, and significant numbers of astrologers

prowled the streets of Rome and the major cities of the Empire.130

Augustus apparently made use of astrology, his own destiny being allegedly

predicted early in his life,131 and it was late in the Augustan period that

Manilius began the Astronomica. The link between the Imperial government

and astrology continued with Tiberius who possessed the first recorded


129 The growth in appeal of astrology to the Romans may be attributed to a number ofcauses. Barton (1994–2) 33, 38 argues that it played an important part in Romanculture in the Imperial period to the extent that it became an intrinsic feature ofRoman society. She attributes this rise in importance to the growth in influence ofindividuals such as Sulla and Caesar in the first century. This would presumably bein contrast to the traditional divination of the Republic that concerned itself with thefate of the State and not the individual. Plutarch recorded the use of astrology byprominent Romans in the last century of the Republic: e.g. Marius 42.4–5, Sulla37.1. Watson (1992) 60 argues that the official religion of Rome was ‘barren’ inthat it provided little guidance to individuals, being concerned with affairs of State.This left the Roman populace open to the influence of foreign religions in times oftrouble. Jones (1992) 83ff. suggests that Augustus preferred Stoicism to its rivalEpicureanism. I would suggest in addition that the uncertainty caused by the civilwars of the first century as well as a growing appreciation of Greek culture (inparticular Stoicism) also contributed to the rise of astrology.130 MacMullan (1967) 137–8 suggests that the ordinary people had access to unskilledmathematici in the streets of Rome while the better class of astrologer was availableonly to those who could afford their services.131 Suet. Aug. 94.5. Barton (1994–2) 54 argues that Augustus made astrology one ofthe foundations of his government in a fashion similar to Constantine’s adoption ofChristianity.132 Tacitus Ann. 6.21 describes the significant influence that Thrasyllus had withTiberius. Thrasyllus would have provided a model for all aspiring astrologers. Hewas plucked from relative obscurity, became an intimate of the emperor and then hisfamily remained prominent in Imperial circles for several generations. For a furtherdiscussion of Tiberius and Thrasyllus see Levick (1976) 18, Barton (1994-1)43-4 and Kaplan 43-9.

court astrologer, Thrasyllus.132 Later emperors continued this tradition

court astrologer, Thrasyllus.132 Later emperors continued this tradition

while displaying various degrees of credence to the art.133

Astrology was a two-edged sword due to its perceived ability both to

support and to harm the reigning emperor. It was possible for one astrologer

to assist the emperor by adding astrological lustre to his rule, while another

was aiding his opponents by predicting the emperor’s mortality and naming

his successor.134 At various moments of instability the emperors felt it

necessary to expel astrologers from Rome.135 These expulsions were perhaps

not always too severe and often included not just astrologers but also

philosophers, magicians and mathematicians. These practitioners may,

after a safe period of time, have returned to Rome. This dilemma, the

usage of astrologers by both emperors and their enemies, appears to have

been the problem facing Tiberius in A.D. 16 with the assassination plot of

Libo Drusus136 and the trial of Aemilia Lepida in A.D. 20 on the charge


133 On astrology under the later Empire see Barton (1994-1) 44-9.134 In A.D. 11 the casting of astrological predictions to determine a person’s longevitywas forbidden by Augustus (Dio Cass. 56.25.5). The emperor Domitian is recorded ashaving cast the horoscopes of prominent men so that those whose futures indicated thepossibility of attaining the purple could be executed (Dio Cass. 67.15.6).A description of the role of astrologers in the Roman government occurs in TacitusHist. 1.22 where Tacitus alleges that astrologers urged Otho to revolt (...quod incivitate nostra et vetabitur semper et retinebitur). Astrologers seem to have gainedinfluence in periods of social unrest. MacMullen (1967) 131ff. argues that allemperors had an ambiguous relationship with astrologers, alternatively using themto bolster their rule and then avoiding the undesirable consequences of their predictions.135 Prior to the Imperial period, but illustrative of the potential of astrologicalprediction in times of difficulty, is the Sicilian slave revolt of Athenion who wasdescribed as an astrologer and who predicted his own victory and inspired his followerswith this prediction, (Diod. Sic. 36.5). During the Imperial period, Augustus destroyedcopies of works on divination (Suet. Aug. 31.1). MacMullan (1967) 134 lists adozen trials in the first century concerning the use of astrology by prominent figureswho sought details of the emperor’s destiny. Astrologers are known to have beenexpelled from Rome in the years: 139 B.C., 30 B.C., A.D. 16, A.D. 52 and A.D. 69,also in the reign of Domitian and Marcus Aurelius.136 Tac. Ann. 2.27-32, cf. Barton (1994-1) 44.137 Tac. Ann. 3.22-3.

of consulting astrologers concerning the imperial house.137 Tiberius resolved

of consulting astrologers concerning the imperial house.137 Tiberius resolved

this situation by evicting all astrologers, bar his own.

It was in this period that Manilius wrote the Astronomica, a work clearly

intended for the elite. The Astronomica is careful to praise Rome, the

Imperial system, Augustus and Tiberius. Manilius’ astrology is similarly

cautious. He refers to fate granting Rome its place in the world but gives

no specific examples of contemporary horoscopes. He provides a number

of different astrological formulae but does not state precisely how they

are to be used. In the Astronomica we find a poet who carefully seeks to

demonstrate the usefulness of astrology to the existing political system

and dynasty without threatening it in anyway.

______________________The Beliefs and Personality of Manilius 83

2.2 The Beliefs and Personality of Manilius

2.2.1 Introduction

The Astronomica contains virtually no autobiographical information. There

are only a few scattered, indirect references to the poet. The major clues

to Manilius’ personality and beliefs are the attitudes expressed in the text

of the poem. These clues, and the Astronomica itself, do make possible a

number of broad statements about the poet’s nature, character and

circumstance. I am aware of the difficulties and controversies surrounding

the analysis of poets and their work. In this section of my thesis I do not

wish to add to this literary debate, rather to draw what may seem obvious

conclusions from my understanding of the work.

2.2.2 Personality

The clearest indication we have of Manilius’ personality lies in his

dedication to his task. Whatever its failings, the Astronomica is a complex

work showing a wide-ranging knowledge of Stoicism, astrology and

astronomy. It would have required a great deal of time and commitment

to write.138 This indicates the strength of Manilius’ passionate belief in

Stoicism and astrology, to him, the pinnacles of human achievement.139

On a more prosaic question Manilius must have had sufficient time and

resources to devote himself to the lengthy task of composing the


138 Horace’s account of the life and dedication of a poet would be in agreement withManilius’ view (Ep. 2.1.126). Quinn (1979) 127 states that didactic poetry hadbecome popular in Manilius’ era and refers, somewhat unflatteringly, to the ‘dilettantepoet’.139 e.g. 2.105–136.

Astronomica, which suggests that he may have been from a well to do

Astronomica, which suggests that he may have been from a well to do

family,140 and from his name it would seem that he was of Italian/Roman

stock.141

Manilius regards his work as of great and unique worth. In his opening

lines the poet states that he follows two goals, his theme and his poetry

(1.20–4). He not only regards his message as important but also its

medium.142 Book Two begins with a line of descent from Homer and

Hesiod, but this catalogue is used to demonstrate that Manilius is better

than his predecessors (2.1–27). He places himself in a catalogue of poets,

not of philosophers. He describes himself as a teacher of humanity and

adopts a didactic tone throughout his work. He even goes so far as to

explain his didactic method (2.751–87).

The one reference of a purely personal nature occurs in 1.113–7. Here

Manilius asks for a long life to allow him to complete his task. Goold

believes that Manilius therefore was no more than ‘middle-aged’ at the

time of composing Book One.143 Though this is conceivable, another

interpretation is that Manilius was well past middle-age and asking for

enough time to complete the Astronomica. We can say no more than the

poet was at least middle-aged c. A.D. 14, thus born perhaps c. 30 B.C.


140 There is no suggestion of a patron in the Astronomica, nor of an interlocutor.141 cf. Goold (1977) xii-xiii. Pliny Nat. Hist. 35.199 refers to a Manilius Antiochusas the founder of astrology in Rome. Rackman (1968), in a footnote to his Loebtranslation of Pliny (408, n. b), states that Manilius was ‘Probably father orgrandfather of Manilius who wrote the extant Astronomica.’ This statement is madewithout any supporting documentation. We have no evidence of our Manilius’ ancestryor any reliable indication of his origin. The Prosopographia Imperii Romani 155entry for our Manilius states that nothing, apart from his composition of theAstronomica, is known of his life.142 As Quinn (1979) 123-4 suggests, didactic poets saw their work not merely as asource of information but as works of literature.143 Goold (1977) xii.

From his use of Greek astronomical information, we can assume that

Manilius was conversant with Greek, perhaps more so than would be

common even amongst upper-class Romans. It is possible that Manilius

was part of a small group of intellectuals, possibly headed by Thrasyllus,

who were close to the Julio-Claudian court. As Goold suggests, Manilius

may have been part of a Greek ‘professorial’ circle at Rome.144

There is one other possible clue to Manilius’ identity. In 4.152–61 (in

particular 4.158–60) Manilius refers to those born under Gemini as poets

and astrologers:

Mollius e Geminis studium est et mitior aetas

per varios cantus modulataque vocibus ora

et gracilis calamos et nervis insita verba

ingenitumque sonum: labor est etiam ipse voluptas.

arma procul lituosque volunt tristemque senectam,

otia et aeternam peragunt in amore iuventam.

inveniunt et in astra vias numerisque modisque

consummant orbem postque ipsos sidera linquunt:

natura ingenio minor est perque omnia servit.

in tot fecundi Gemini commenta feruntur.

It is entirely possible that Manilius considered Gemini to be the abode of

astrologers (and poets) as it was his sign.

2.2.3 The Imperial System


144 id. (1961).

Manilius refers to the Roman world and its rulers a number of times,

Manilius refers to the Roman world and its rulers a number of times,

invariably in a laudatory manner. In 1.7–9, Manilius makes his first mention

of ‘Caesar’

hunc mihi tu, Caesar, patriae princepsque paterque,

qui regis augustis parentem legibus orbem

concessumque patri mundum deus ipse mereris,

In this Manilius may be compared to Virgil who dedicates his Georgics

to Augustus.145 Manilius shows his support for the Imperial regime,146 and

praises it repeatedly throughout the Astronomica. The Roman Empire is

praised not merely because it is a desirable goal, but because Stoicism

requires its existence.The Roman State is fated, as is everything else.

Manilius illustrates this by using the hierarchy of faint and bright stars as

a simile for the social hierarchy present in Roman society 5.734–9:147


145 Georg. 24ff.146 The format of these references changes but the central message is clear. Maniliusrefers to Augustus and the Imperial system both directly and indirectly in the courseof his work. A summary is included here:1.7–10 Introduction and dedication to Augustus.1.385–6 The major difference between the unseen southern world

and the northern is Augustus.1.798–9 Julius Caesar has a divine nature.1.800–1 Augustus has a divine nature.1.922–6 Augustus brought peace.4.547–52 Libra is the sign of the emperor.4.763–77 Rhodes, Libra and (indirectly) Tiberius.4.935 Augustus as ruler of heaven.5.509 Augustus as giver of gold to temples.Ovid Ex Pont. praises the imperial family in a similar fashion, e.g. 4.6.17 and4.9.131-4 where he refers to Augustus’ deification and 4.9.39-54. where Oviddescribes the consul offering thanks to the ‘Caesars’.147 These lines clearly refer to the Roman State, but, they make no mention of theemperor. It is possible that, as Augustus restored the Republic, there was no neednor place for him in this list of the Roman hierarchy. His presence was implied andknown to all.

utque per ingentis populus discribitur urbes,

principiumque patres retinent et proximum equester

ordo locum, populumque equiti populoque subire

vulgus iners videas et iam sine nomine turbam,

sic etiam magno quaedam res publica mundo est

quam natura facit, quae caelo condidit urbem

Manilius also uses astrology to prove that human nature is intrinsically

evil, justifying the presence of a strong ruler who can prevent the anarchy

that is always waiting to emerge (2.579–607). This is a sublimated theme

in the dedicatory lines of Book One, where Manilius praises Augustus for

bringing peace, since only in times of peace is a work such as his possible

(1.13; hoc sub pace vacat tantum ...).148

In the closing lines of Book One, Manilius also asks fate for a continued

cessation of wars and indirectly praises Augustus for this achievement,

1.922–6:


148 There is a belief that there was a ‘Republican’ movement of Stoics in the earlyEmpire (Jocelyn (1977) 326–7). Brunt (1975) 7–35 discusses the history of theStoics during the principate at some length. He finds a somewhat ambivalent relationshipbetween the two. He states that Cato the Younger’s life was a model for Stoics such asSeneca and that a purge of Stoics occurred under Nero (Manilius 4.87 refers to Catofavourably). Evidently there was no ‘one’ Stoic view of the Empire. Individuals foundtheir own version of Stoicism.A somewhat critical statement concerning the ‘pro-Imperial’ nature of Roman Stoicismis made by Arnold (1911) 303 who states that after Panaetius and his successors,“The daring moral theories and bold paradoxes of the founders of Stoicism tend todisappear from sight and are replaced by shrewd good sense and worldly wisdom: inshort by the doctrine of ‘making the best of both worlds’.”

...iam bella quiescant

atque adamanteis discordia vincta catenis

aeternos habeat frenos in carcere clausa;

sit pater invictus patriae, sit Roma sub illo,

cumque deum caelo dederit non quaerat in orbe.

Such an attitude towards Augustus is not surprising. Those who grew to

maturity during or at the end of the civil wars (Manilius was possibly a

generation younger than Augustus) would appreciate the stability and

security of the Augustan achievement.149 This conclusion does make

possible one further interpretation of Manilius’ attitude to the regime. It is

clear that he held Augustus and his system in high regard, but the text

also indicates that support of the State was not Manilius’ ultimate goal.

Manilius reserves his most ardent and direct homage of Augustus for

Book One. Then Manilius begins his true work, expounding Stoic destiny.

From here, the frequency and magnitude of the references to the Imperial

system decrease.150 This suggests that Manilius, grateful as he was, saw

the Augustan era as merely the historical epoch which allowed him to

expound Stoicism.

2.2.4 Manilius as an Observer of the Heavens

Both modern and medieval astrologers relied more on tables and charts

than on actual observations of the heavens for their calculations. This

separation of observation from prediction is a natural consequence of a

highly ritualised style of astrology that did not rely exclusively on the


149 Praise of Augustus is found in every major work of this period, Sikes 88ff.150 Domenicucci (1993) 222 comments on the less than expected number of referencesto the divine aspects of the Imperial family.

actual appearance of the heavens but used the heavens as a starting point

actual appearance of the heavens but used the heavens as a starting point

for the subtle calculations based around astrological concepts such as the

athla described in chapter Six. The astrological theories outlined in Books

Two to Five could be implemented without actual observation, using data

derived from charts of the heavens and tables of phenomena.151

There is evidence in the Astronomica, however, that Manilius did observe

the heavens. Manilius was not primarily an astrologer, but a Stoic. As he

believed that the heavens were divine, an interest in their actual appearance

might have resulted from his philosophy. The first example of Manilius’

observational interest is his discussion of the ‘dimming effect’ of a full

Moon 1.469–73:

praecipue, medio cum luna implebitur orbe,

certa nitent mundo tum lumina: conditur omne

stellarum vulgus; fugiunt sine nomine turba.

pura licet vacuo tum cernere sidera caelo,

nec fallunt numero, parvis nec mixta feruntur.

The full Moon’s bright light (and that at least five days before and after

the full Moon) drowns the light of the fainter stars, making the pattern of

the constellations more easily discernible to the unskilled eye. This was

no doubt a well-known observational technique in the ancient world.152

The poet could have added it to the Astronomica merely from the reports

of others, yet its inclusion does suggest the possibility of its use, or at


151 We can surmise, based upon the accuracy of the calculations of astronomers suchas Hipparchus and upon a few surviving examples, that ephemerides of similaraccuracy and detail existed at least from the second century B.C. Jones (1995)255-8 describes one such ephemeris (dated to c. A.D. 100), which may describe thedaily position of four planets.152 It is a technique used in the modern world.

least its verification as a technique by Manilius himself.

least its verification as a technique by Manilius himself.

Another indication of Manilius’ observations is his description of the

colour of the star Sirius.153 There are a number of ancient authors who

state the belief that Sirius was red. This is due to its colour at its often

observed heliacal rising (when its colour is caused by atmospheric

scintillation), and its astrologically perceived evil nature. Manilius does

not follow this belief and states that Sirius was blue/white, its (modern)

true colour (1.409): frigida caeruleo contorquet lumina vultu. As Manilius

was an astrologer, it would have been reasonable for him to repeat the

claim that Sirius was red, indicating its evil effect. As he did not, his

statement strongly suggests that he was familiar with, and took account

of, the true appearance of the heavens, to the extent that this took precedence

over belief.

These points suggest that Manilius did take the trouble to look at the

sky,154 and may have even enjoyed doing so, however, they also tell us

that he was not concerned with the mechanics of actual observation.

Manilius did not include any basic information about his own observing

habits. There is no mention of the instruments (if any) he used to observe

the stars, there is no description of his location, nor is there a reference to

charts or tables available to an astrologer. His general attitude to astronomy

is that of a theoretician, not of an active observer.

While none of these arguments is conclusive, they do suggest the possibility

that Manilius was, at least to some extent, an observer of the heavens. If

so, he differs from later Stoic authors who moved into a more abstract


153 This is discussed fully in chapter Four, ‘The Colour of the Star Sirius’.154 Manilius states that Venus appears as both an evening and a morning star in thecourse of the same day (1.177ff.). This is incorrect, but he uses it to bolster hisargument. This obvious error does argue against Manilius’ diligence as an observer.

world where belief controlled observation and not vice versa.

world where belief controlled observation and not vice versa.

2.2.5 Manilius and Mathematics

One may also conclude that Manilius was not fluent in mathematics.

While he clearly drew on a number of mathematically oriented astronomical

sources for the Astronomica, he created a sphaera, not a catalogue. His

decision to compose in verse, and not prose, would have reduced the

amount of mathematics that could have been included in the Astronomica,

but, if he had wished, Manilius could have included far more in his

discussion of astronomical and/or astrological calculations.

On one occasion, Manilius illustrates his work with a mathematical example.

In lines 1.539–56, he describes the Euclidian relationship of the

circumference of a circle to its diameter in order to describe the relative

size of the universe. A simple method of incrementation is used to describe

the horoscope formulae of Book Three, but the level of mathematics used

is not very sophisticated, and its inclusion does not suggest a high degree

of proficiency by the author.

On other occasions when mathematics could have been used to better

illustrate a point, or to explain astrological calculations, they are not.155

The impression here is that Manilius knew just enough mathematics to


155 An example of this is the description of equilateral triangles given in 2.273-8.Manilius in a clumsy fashion describes the ‘equal’ angle possessed by each ‘corner’ ofsuch a triangle. While this is correct it would have been simpler to specify the angleof each intersection and the length (in signs) of each side of the triangle.

carry out basic astrological procedures and no more.

carry out basic astrological procedures and no more.

2.2.6 Manilius as an Astronomer

In chapter Three I will discuss Manilius’ astronomical knowledge. As a

background to this I shall now look at his attitude to the field as a distinct

whole.

What is immediately clear from the astronomical information supplied in

Book One is that Manilius did have a good, though somewhat varied,

understanding of most aspects of ancient astronomy. His weakness seems

to lie in his understanding of mathematical astronomy and in areas that

might undermine his belief in astrology. This conclusion should not be

taken as an indication that the poet had no personal interest in the field.

Manilius does include a few points that indicate his attitude to astronomy.

The first of these is in lines 1.13–5:

hoc sub pace vacat tantum. iuvat ire per ipsum

aera et immenso spatiantem vivere caelo

signaque et adversos stellarum noscere cursus.

Manilius seems to be saying that he enjoys or finds delightful the study of

the heaven, which is hardly surprising. The Astronomica was an immense

work, and its author must have had a strong motivation to begin and to

complete the text. The reference to ‘signs’ and ‘planets’ (1.15) suggests

the possibility that Manilius may have been describing his interest in

either astrology or astronomy, although, the two lines immediately

following resolve this question (1.16–17):

quod solum novisse parum est. impensius ipsa


scire iuvat magni penitus praecordia mundi

scire iuvat magni penitus praecordia mundi

These lines clearly refer to astrology. Thus in the four lines 1.15–7,

Manilius was describing his affection for both astronomy and astrology,

and thereby indicating an awareness of a degree of distinction between

the two. Manilius also separates the two in lines 1.118–21, where he

states that he must first describe the true appearance of the heavens before

he can discuss astrology. Manilius possibly divided the two into the

observational side of astronomy and the theoretical calculations of

astrology. Assuming this to be the case, we can conclude that Manilius

had an interest in the observation of the heavens in itself, which is a

sentiment implied throughout the Astronomica. In this, Manilius differs

from other Roman astronomical authors. While both Cicero and Seneca

composed astronomical writings, neither was overly involved in

observational astronomy. Cicero’s astronomical writings are based around

Aratus, while Seneca, with references to astronomically impossible ‘red

comets’, (NQ. 7.15.1 Primo igneus ac rubicundus orbis fuit clarumque

lumen emittens) did not describe the visual appearance of what he saw.

Another factor that suggests Manilius’ appreciation of astronomy is the

abundance of astronomical information in Book One that is superfluous

to the astrology of the later books. As discussed in the summary of Book

One (thesis section 1.2), much of the astronomical information could be

removed from the text with no effect on the astrological matter. Its inclusion

suggests that Manilius had an interest in astronomical matters, beyond

that which underpinned his astrology. This is further suggested by the

wide range of sources he uses in his astronomical writings.

This interest in astronomy by Manilius should not be taken as an indicator


that he was an ‘astronomer’ lurking beneath the guise of astrologer. Manilius

that he was an ‘astronomer’ lurking beneath the guise of astrologer. Manilius

was first and foremost a Stoic astrologer, and astronomy was completely

subordinated to this end. If we consider that there were two schools of

thought in the ancient world,156 one ‘scientific’, as typified by Eudoxus

and Hipparchus, the other ‘mystic’ as typified by Pythagoras and Plato,

we can see that Manilius falls into the latter. Plato lists astronomy as one

of the five mathematical disciplines necessary for a good education.157 It

is clear from this description that observational astronomy was not the

goal of Plato’s exercise, and the ‘philosopher Kings’ were to gain knowledge

of divinity by looking for the higher truths behind the display of the

heavens. In the Timaeus Plato states that astronomers—men who look to

the visible heavens for truth—are reincarnated as birds for their

foolishness.158 This is the view that Manilius shared of the heavens. By

investigating the motions of the stars and planets one could look past

them and discover the true nature of the universe. It is unstated in the

Astronomica but I feel that Manilius shared Plato’s attitude to astronomers.

2.2.7 Manilius’ Stoicism

This discussion provides an overview of the philosophical thought found

in the Astronomica in order to determine its substance and gaols, to

identify its Stoic nature clearly, as well as to place Manilius in the


156 The division of Greek thinkers into two ‘schools’ is to a large extent an arbitraryone. Many, such as Eudoxus, a student of Plato, had a foot in both camps. It ispossible, however, to detect a ‘secular’ and a ‘divine’ approach in Greek thought tounderstanding the universe. From the above paragraph there is also the question ofthe correct interpretation of Plato’s writings. Plato was limited by the tools of hisday and should be seen as a thinker situated at the beginning of the astronomical era.Taking this into account it is still clear that Plato saw the heavens, not as significantin themselves but as representing the hidden divinity of the universe. Manilius issquarely placed in this category.157 Plato Republic. 529–530c.158 Plato Timaeus. 91.D.

development of Stoic thought.

development of Stoic thought.

What first emerges from an examination of the text is the central importance

of Stoicism to the poem and the clear indication that Manilius was an

ardent Stoic, since all aspects are presented and interpreted from a

demonstrably Stoic perspective. Manilius seems to have seen Stoicism as

the peak of human achievement and to have viewed astrology as the

philosophy’s greatest manifestation. He constructed the poem as a vehicle

for these beliefs. Thus the Stoic information provided is designed to

achieve two goals: first, that of explaining and describing the divine

destiny that awaits enlightened human beings; and secondly, that of

providing a rationale for astrology.

Stoicism was divided into three categories; physics, logic and ethics,159

but of these three, logic is not mentioned in the Astronomica and ethics is

discussed only briefly.160 Manilius evidently concentrated only on the areas

that interested him: physics and, in particular, Stoic astrology and the

related themes of astronomy and cosmology.161 This approach seems to

have placed Manilius at odds with earlier Stoic authors, since it is said

that the major Stoic figures taught all three areas and considered each to

be necessary for an understanding of the whole.162 Thus the philosophy

found in the Astronomica should be viewed only as a component of the


159 Diog. Laer. 7.39–41 describes the triple division of Stoic belief.160 One question emerging from a belief in a completely fatalistic universe is thenature of good and evil. If human actions are fated, can a person be truly good or evil?Manilius answered this question in his one discussion of ethics. He states that gooddeeds should be doubly praised, as they are ordained by fata and caelum and that thereverse is true for evil deeds (4.110–21). This was an early question in Stoicism,as Diogenes Laertius records Zeno dealing with this very matter (7.23). Maniliusalso criticises human preoccupation with luxury (4.402–5) but his argument suggeststhat he is concerned that material interests might detract from an interest in Stoicismand astrology.161 Colish (1985) vol. 1, 22–3.162 Diog. Laer. 7.39–41.

complete corpus of Stoic thought.163 We might conclude that Manilius

complete corpus of Stoic thought.163 We might conclude that Manilius

viewed human destiny via astrology as the only significant component of

Stoicism. The poem was clearly intended to convey this brand of Stoicism

to the reader and, however narrow the perspective of the Astronomica, it

still casts a measure of light on the nature of Roman Stoicism.164

As well as presenting Stoicism and astrology to the world, the Astronomica

may be viewed in the light of a contemporary controversy. Manilius

might have intended the Astronomica to be a rebuttal to the De Rerum

Natura of the Epicurean author Lucretius, whose work was diametrically

opposed to the creed of Stoicism and to astrology. This philosophical

conflict had historical roots. From their beginnings proponents of Stoicism

and Epicureanism had engaged in debate and rivalry.165 Manilius almost

certainly saw his work as a further polemic (if not the final word) in this

debate.166 A wide chasm existed between the Epicurean astronomer

Lucretius, who saw a random universe as a manifestation of blind chance,

and the astrologer Manilius, who perceived it as the creation and


163 Hahm (1977) 231 suggests that Chrysippus wrote over 750 volumes of Stoicbeliefs.164 Manilius lies in an intermediate stage in Stoic development. The ‘Middle Stoa’ended with Posidonius, the ‘Roman Stoa’ began with Seneca. Between the two, the onlyextant Stoic author of note is Manilius. The ‘Middle Stoa’ was concerned with the fullrange of Stoic thought, but the Roman period became preoccupied almost exclusivelywith the question of ethics. Manilius seems to chart a third course, concentrating onastrology and fate.165 Hahm (1977) 120–1 argues that Lucretius specifically intended his work to be arebuttal of Zeno’s and (in general) Stoicism’s cosmology. This animosity is basedupon the long-existing rivalry between two of the major philosophical systems of theclassical world. See Colish (1985) 1.9 for an introduction to this conflict. Thiscriticism of Epicureanism and in particular its ‘atomic’ nature may have placedManilius at odds with Thrasyllus who apparently edited both Plato’s (Diog. Laer.3.56ff, cf 9.45) and Democritus’ works (Diog. Laer. 9.41ff.).166 cf. Sikes (1923) 172, 176 who states that Epicureanism had fallen from favourin the Augustan period and views the Astronomica as a political attack on de RerumNatura. An example of Manilius’ antagonism is found at I.486–94 where he criticisesEpicurean beliefs.

manifestation of divine order.167

manifestation of divine order.167

One feature of Manilius’ Stoic poem is that, while it does acknowledge

Greek and Roman military and political heroes, it lacks any reference or

recognition of any debt to earlier Stoics. The only mention of philosophers

lies in Book One where Manilius lists as having animi vires: Solon,

Lycurgus, Plato, Socrates and Themistocles (1.771–6). This omission

suggests that Manilius saw himself and his work as a substantial

improvement upon the work of his predecessors to such an extent that he

felt no need to mention any by name.168

2.2.7.1 Stoicism in the Astronomica

The theory of Stoicism is presented in five separate sections of the text

totalling approximately 700 lines, or 15 per cent of the work. The first

section in lines 1.25–254 provides an overview of Manilius’ Stoicism.

Here the Stoic God is introduced, as is a history of humanity, cosmology

and a presentation of astronomy. The topics that are found throughout the

rest of the Astronomica are first discussed at an introductory level in

Book One.

The second discussion occurs in the opening lines of Book Two (2.60-87).

Here Manilius places his poem and himself at the peak of classical poetry.

He discusses the dominance of God and the divine potential of human


167 Sikes (1923) 162–3 states that Lucretius saw the universe in purely scientificterms. This would be in sharp contrast to Manilius and the Stoics.168 We might surmise that the first four were included as Manilius considered themthe founders and protectors of the Greek philosophical world. Hahm (1977) 209argues that Stoic physics was based upon the work of Plato and Aristotle. This mayhave been the specific motivation for the inclusion of Plato. Themistocles was includedas Manilius considered him responsible for defeating the Persian invasion and savingthe Greek world, 1.776.

beings. It is here that Manilius first looks at fate and astrology in detail.

beings. It is here that Manilius first looks at fate and astrology in detail.

The third discussion is found in lines 3.1–95, which concentrates on

astrology, explaining its place in the Stoic universe.

The next area of Stoic exposition is found in lines 4.1–121, where Manilius

expounds upon fate in great detail, depicting it as pervasive and fickle.

The last philosophical discussion in the Astronomica is found at the end

of Book Four, lines 866–935, which provide a summary and conclusion

to the work.169 It reiterates the case concerning Stoicism and astrology and

then argues for the divinity of human beings and their relationship to

God. The tone of this statement and its placement in the conclusion

suggest that this last point is the aim of the work (cf. thesis section 1.2.5,

1.2.6). Book Five contains no Stoic references.

2.2.7.2 Manilius’ Means of Argument

From the discussions of Stoicism in the Astronomica, several comments

can be made concerning the means Manilius has used to present his

beliefs and his competence in doing so. The methodology used by the

poet is described in 2.751–87. It is a didactic, educative system, one he

believed would best convey his beliefs by presenting the reader with

consecutive accounts of a topic with each successive account becoming

more complex and providing greater detail than its predecessor.

In his work Manilius used this approach as a basis for his account of

Stoicism. Each of the five separate Stoic discussions centres around one

or more main topics, but each includes other, complementary, information.

The discussions are constructed so that what first appears as a minor topic


169 As discussed in the summary of the Astronomica, Book Four forms a naturalconclusion to the work.

becomes a major topic in a following discussion, and then it is found

becomes a major topic in a following discussion, and then it is found

restated in different guise and with a different emphasis in subsequent

discussions as a minor topic again. The opening lines of Book Four, for

example, discuss fate as their primary argument. Fate has been discussed

in earlier sections, but now it is repeated in greater detail and with more

emphasis. Manilius seems to have broken down each argument into its

smallest components and then placed these together in such a way that

they reinforce each other without contradiction. There is also an ‘emotional’

belief created by this style of presentation. A reader, who might not grasp

the work intellectually, might find that the continual, unobtrusive repetition

of material, reinforced a belief in the conclusions of the work.

Another aspect of Manilius’ methodology is the relative allocation of

attention to each topic in accordance with its importance to the poem.

Cosmology, for example, is primarily treated in Book One, with minor

references to it in the remainder of the work. This suggests that, while a

knowledge of cosmology is necessary to the reader, it is not the central

message that Manilius is wishing to communicate. Fate, by contrast, is

discussed throughout the Astronomica with the final discussion occurring

in Book Four, suggesting that it has a far greater importance.

Another major feature of Manilius’ means of argument is the creation of

an internally logical and even ecumenical argument with respect to Stoicism.

In his model of the universe, Manilius has created not a linear but a

circular hierarchy. It begins with God, and proceeds through various aspects

of the universe, including cosmology, fate, astrology and then human

beings. Humans are then linked back to God to complete the circle of the

Stoic universe. This circular unity of the universe would be enticing to


those looking for a belief based upon logical certainty.

those looking for a belief based upon logical certainty.

To summarise, Manilius uses repetition and a structure of accumulation

to create a persuasive argument for belief in his brand of Stoicism. The

interested reader would find this in itself compelling. When we add to it

the complex astrological theories, the engaging belief that human beings

are in some way divine (and immortal) and the elitist nature of the work,170

then the same reader might be overwhelmed by the barrage of convincing

argument for the worth of the Astronomica. Manilius’ talent as a didactic

poet is no better illustrated than by his ability to create a convincing

argument for Stoicism.

2.2.8 Conclusion to Manilius’ Beliefs and Personality

Due to the limited nature of the evidence in the Astronomica, it is difficult

to reach firm conclusions regarding Manilius’ biography. It is clear though

that, in the Astronomica, Manilius dedicates his work to Stoicism and

astrology. He sees himself as being present in a new era of humanity, one

in which his account of destiny is to be disseminated amongst those few

who can appreciate it. He rejects material wealth as unimportant compared

to Stoic, astrological divinity. He indicates the rarity of morality in human

beings and the fickleness of friendship, and he expresses a harsh view on

crime and punishment. It is not unreasonable to conclude that Manilius

saw human society as a mere precursor of its ultimate fate, that Stoic

destiny which he expounded in the Astronomica, or that he very likely

saw himself as a lone, prophetic figure carrying the light of truth to

humanity.


170 In 2.137ff. Manilius states that he composes only for a few and not the many, necin turba nec turbae carmina condam sed solus.

Manilius’ account of Stoicism is consistent and studied. He introduces his

Manilius’ account of Stoicism is consistent and studied. He introduces his

subject, argues its validity, and then carries the argument to a higher level

of understanding as he progresses through his work. At each stage argument,

rhetorical questions and answers, examples, appeals to reason, comparisons

and a variety of other techniques are used to persuade the reader to accept

his beliefs.

In his discussion of Stoic concepts there are obvious minor inconsistencies,

but these can be accounted for as questions of cultural context. We can

conclude that Manilius believed that the existence of humanity was central

to Stoicism; that human beings were unique in the universe, possessing

and forming a part of the Stoic divinity of the universe; and that animals

were not part of this divinity. The greatest human achievement lay in

humanity’s comprehension of the Stoic universe and of the central role of

humanity and the existence of a divinity in human beings. Manilius’

universe begins with the Stoic God who created the universe, the Earth

and human beings. The human beings who first lived in this universe

existed in fear and ignorance, unknowing of their divine origins and

potential. After a long struggle to master lesser arts, human beings managed

to find their path to heaven by their study of, and devotion to, Stoicism

and Stoic astrology. The conclusion of this knowledge is the discovery

that human beings possess a component of the Stoic divinity and are

themselves divine. In achieving this understanding, the Stoic has closed a

circle that began with God.

It is also possible to conclude that Manilius did have an appreciation of

the heavens over and above that required for astrology. Manilius was an

observer of the heavens, a practice not necessary for his astrology, and

his knowledge of astronomy was greater than that necessary for astrology.


There are also indications in the Astronomica that Manilius did differentiate,

There are also indications in the Astronomica that Manilius did differentiate,

to a certain extent, between astronomy and astrology. The extent of this

separation is unclear. It is unlikely however, that Manilius saw two separate

disciplines; his obsession with astrology would preclude the appreciation

that astronomy could be a goal in itself. To Manilius, astronomy was an

important but subordinate component of the art of astrology.

The Astronomica is a reasonable but somewhat jumbled explanation of

the non-mathematical basics of ancient astronomy. By comparison, the

level of knowledge presented is greater but less consistent than that found

in Aratus.171 The ostensible purpose of Manilius’ astronomy was to provide

a basis for his astrology. In this, it does provide a starting point, but only

just.

The cause of Manilius’ failure as an astronomical poet is his lack of a

comprehensive and coherent structure for the topic. This reflects his

approach to astronomy and his work in general. The aim of the Astronomica,

however, was to convince the reader of the worth of Stoicism, everything

else was secondary. In his account of astronomy, there are gaping holes,

which to him were not only unimportant, but invisible. Manilius used

whatever information he felt necessary at each section of the work to

prove what he was discussing.

____________________________Astronomy in the Astronomica 103

171 Cicero used Aratus as his source of astronomical information. Presumably Maniliusexpected his readers to have a greater knowledge than might be thought sufficient forthe average well-educated Roman.

3. Chapter Three: Astronomy in the Astronomica

3.1 Introduction

The primary goal of the Astronomica is to explain the divine nature of

human destiny in Manilius’ Stoic universe to a small group of savants.

This explanation revolves around a belief in fate, the mechanics of which

are made known to human beings by astrology. Thus the bulk of the

Astronomica is given over to a discussion of astrology within a Stoic

context. Books Two to Five contain exhaustive descriptions of astrological

theory and technique. This relegates the discussion of astronomy to a

distant place compared to the dominant theme of the Astronomica, yet

Manilius did believe that an understanding of astronomical theory was

necessary before a mastery of astrological theory could be achieved

(1.120–1):

ipsa mihi primum naturae forma canenda est

ponendusque sua totus sub imagine mundus

It is evident that Manilius considered astronomy to be an essential

prerequisite to astrology. In this he is not alone. Ptolemy, writing more

than a century after Manilius, adopted the same approach, albeit in far

greater depth. Ptolemys’ astronomical Almagest provides the foundation

for the study of astrology in the Tetrabiblos. This attitude to astronomy

and astrology is not universal. Cicero provides an alternative view. In de

Div. 2.10, he states that those who practise divination would not know

astronomy. This, given in the context of an argument against divination,

may reflect the capabilities of the less than philosophic soothsayer rather


than the Stoic astrologer. Manilius saw the heavens as a manifestation of

than the Stoic astrologer. Manilius saw the heavens as a manifestation of

God and reasoned thus, that to know the heavens is to know God, but to

know the heavens one must first learn the basics, and this is what he

attempts to impart in his accounts of astronomy.

As well as a theoretical presentation of astronomy, the poem includes a

substantial amount of astronomical background material relating to the

astrological procedures of the later Books. The sum of this material provides

a wide-ranging account of ancient astronomy which permits us the potential

for an examination of the state of astronomical knowledge of the time.

Before we can examine this material in detail, it is desirable to review the

precise nature of Manilius’ astronomy to determine its reliability and

worth.

The most consistent account of astronomy is found in Book One, yet even

in this account, intended to be the major presentation of astronomy, there

are significant omissions and variations in quality. The principal component

of this introduction is a discussion of positional astronomy in the form of

a descriptive account of the heavens, a sphaera. A number of important

topics are discussed, which include: cosmological theories (1.118–254), a

constellation catalogue (1.255–531), the celestial circles (1.539–804) and

a rambling and confused description of comets and meteors (1.809–926),172

but other topics that would prove useful to the reader are ignored. These

gaps include mathematics, observational techniques, the use of charts and

tables, astronomical instruments and a detailed account of the planets and

eclipses.

Manilius was equally cavalier in his use of sources and consistency of


172 In this account, Manilius seems to have confused comets and meteors, two separatephenomena.

approach in Book One. For example, the description of celestial circles

approach in Book One. For example, the description of celestial circles

(1.539-804) uses a sexagesimal degree system, while elsewhere in the

poem a 360 degree system is in use. The planets are only briefly mentioned.

The descriptions of the Milky Way (1.684-804), and of comets and meteors

(1.809-926), are distinctly different from the description of the celestial

circles, being both astrological and mythological in orientation. The

summary form of the astronomy in Book One would not provide the

interested reader with a grounding in astronomy sufficient to understand

the astrology of the later Books, yet this is its stated intention (1.120-1),

and this is the most comprehensive and systematic account of astronomy

in the Astronomica.

Moving beyond the sphaera of Book One, we find an even more varied

selection of astronomical information. It is clear that these later accounts

are not part of a systematic description of astronomy, since each discussion

is complete in itself as it describes and supports a particular astrological

procedure. The best example of this is the ‘horoscope’ formulae of Book

Three. Manilius lists several formulae for calculating the horoscope. They

make use of information that is found in or can be based upon the sphaera

of Book One, but this information is not referred to as an aid in the

mastery of these formulae. Equally, the sphaera of Book One could have

included additional information and emphasis that would have made it of

greater use as an aid to the understanding of the horoscope formulae, but

it does not. In a similar fashion the list of magnitudes of constellations at

the end of Book Five stands alone. The categorisation of constellations by

brightness could have been incorporated into the constellation catalogue

of Book One as an aid to the visual identification of the constellations,

but once again, this was not done.


Book Two provides an astrological description of the seasons and of the

Book Two provides an astrological description of the seasons and of the

Sun’s progress through the zodiac (2.175–265). In Book Three there is

one short but significant reference to the planets (3.61-4), but the

astronomical importance of the book lies in its lengthy and detailed

discussion of the means by which the horoscope (that degree of the zodiac

rising at the time of the subject’s birth) is calculated (3.160–509). This is

an important calculation for astrologers as it was believed, by some schools

of astrology, that this was the key determinant of fate. Book Four contains

only one definite astronomical reference, in which Manilius restates the

fact that a Lunar eclipse is caused by the Earth blocking the Sun’s light

(4.841–7).

Book Five contains a number of astronomical sections, the first being a

brief list of the planets (5.2–7). The bulk of the Book is taken up with an

account of the risings of the non-zodiacal constellations (paranatellonta),

the degree of the zodiac rising with them and their influence over human

destiny (5.32–709). Book Five, and thus the Astronomica, concludes with

a catalogue of constellations in order of brightness (5.710–722). This

catalogue uses the Hipparchian magnitude system.

The result of his approach to astronomy is a disjointed account of the

subject with some topics ignored and others covered to different depths.

This is understandable, if it is remembered that, to Manilius, the provision

of astronomical knowledge was several levels of importance down from

his goal of Stoic destiny. Book One effectively tells us that Manilius did

not consider a unified account of astronomy to be of great importance.

My goal in this chapter is to place Manilius in the history of astronomy

and to determine what light the poem can shed on the astronomical


development of his time. To this effect this chapter will analyse the

development of his time. To this effect this chapter will analyse the

astronomical information found in the Astronomica by identifying the

major topics and then examining the passages relevant to that topic. The

starting points are the topics found in the sphaera of Book One. They

begin with the spherical universe, the shape Manilius believed to be divine.

Every astronomical object in his universe was based upon the sphere and

moved in a circular path. The spherical universe leads into the related

field of the celestial circles, arcs projected onto the sky by terrestrial

astronomy to categorise and delimit the format of the sky. Manilius

described a full complement of circles, indicating an effective grasp of

the fundamentals of positional astronomy. The circles then lead into

Manilius’ catalogue of forty-four constellations. This is a near complete

and well-presented catalogue of the constellations of the ancient world.

Following this are the planets, amongst which Manilius includes the Sun

and Moon along with the five, visible ‘real’ planets. These form the seven

planets of Manilius’ astronomy.173

The comets and meteors discussed at the end of Book One will not be

examined as a distinct topic. As each of these topics is largely distinct in

itself, I have provided a separate conclusion to each discussion. The

summary of Manilius’ astronomy given above provides an overview of

his astronomical beliefs. These four topics (spherical universe, celestial

circles, constellations and the planets) cover the major areas of non-

mathematical ancient astronomy. The final topic of this chapter is a re-

examination of the question of the authorship of the stellar magnitude

system.

___________________Astronomy - The Spherical Universe 108

173 For the sake of simplicity, I will include the Sun and Moon along with the five‘real’ planets in the term ‘planets’. This is in keeping with Manilius’ usage andreduces the redundant descriptions of the objects themselves.

3.2 The Spherical Universe

3.2.1 Introduction

The ancients’ interpretation of the heavens was based on the belief that

the universe was ‘perfect’ and that the Earth and human beings were of

major importance in it.174 Thus the Greeks constructed a model of the

universe based on a geo-centric design, with the heavens moving in ‘perfect’

circular paths. This model was composed of eight spheres centred on the

Earth: the stars, the five planets, the Sun and Moon.175 The stellar sphere

was the furthermost, with each planet attached to a sphere successively

closer to the Earth. The eight spheres rotated around the Earth producing

the apparent movement of the stars, planets, the Sun and the Moon. To

explain the complex and non-circular motion of the planets, additional

spheres were ascribed to each planet, with planets moving successively

from sphere to sphere, changing direction and speed in their journey


174 Dicks (1970) 51 argues that the Pythagoreans were the first to deduce a sphericalEarth and universe. This belief became a central feature of Greek astronomical thought.The origin of this concept of the universe may have arisen from the visual appearanceof the night sky as is a concave ‘bowl’, centred upon the Earth. In addition, the dailypaths of the Sun and Moon across the sky appear curved, fitting the ‘shape’ of thisbowl. There are also a number of terrestrial phenomena suggestive of a sphericalEarth. These include the crows-nest of a ship appearing over the horizon as the shipsails into port, before lower parts of the ship. Neugebauer (1975) 576 suggests thatthe Greeks deduced the sphericity of the earth by, amongst other things, the change inaltitude of circumpolar stars as the observer moves north and south. The belief thatthe heavens are in some sense divine is present in virtually every human culture.The Greek belief that the circle is perfect has its origins in the visual appearance ofthe heavens, the aesthetic appeal of this concept and its ease of mathematicalmanipulation.175 Simplicius, Comm. in Arist. de Caelo 1.12.221, gives a summary of Eudoxus’version of this model. Dicks (1970) 176ff. contains a modern discussion of theEudoxan system, the most complex model of which is preserved by Ptolemy.176 Manilius does not elaborate on this point. The complexities of planetary behaviourwere evidently not of interest to him.

through the sky.176 As an astronomical concept, the celestial sphere is a

through the sky.176 As an astronomical concept, the celestial sphere is a

useful representation of the sky, and it is still used thus in modern

astronomy—but it cannot explain the full range of planetary motion.177

The concept of the geo-centric celestial sphere is accepted without question

in the Astronomica. The heavens and everything found within are described

in this context.178 This belief is expounded to the point where it is not only

the shape of the universe but an intrinsic feature demonstrating the perfection

of the Stoic universe. The principal description of this belief lies in

1.173–246, where examples and argument are supplied in support.

3.2.2 The Overall Shape and Path of the Seven Planets

In keeping with its usage as a piece of background evidence, Manilius

provides only a brief, though comprehensive, description of the exact

structure of the spherical universe. The first mention of this is found in

the introductory lines of Book One (32–3). Here, as part of a general

description of the universe and Stoicism, Manilius mentions perfunctorily

that the Earth is surrounded by ‘paths’:179

sublimis aperire vias imumque sub orbem

et per inane suis parentia finibus astra


177 The geo-centric model of the universe is still in use (navigation, geography etc.)because of its simplicity and ease of use, as compared to models that are moreaccurate in their depiction of the heavens.178 Manilius 1.147–8 states: sed facies quacumque tamen sub origine rerum / convenitet certo digestum est ordine corpus.179 I have made a conscious decision to refer to the movement of Manilius’ planets as‘paths’, not as ‘orbits’. The modern term ‘orbit’ carries with it the baggage ofmodern scientific understanding and a view of astronomy vastly different fromManilius’. To use ‘orbit’ would be to ascribe to Manilius an understanding of astronomythat he did not possess and would not have agreed with.

This is part of the belief, further described in later lines, that the Earth is

This is part of the belief, further described in later lines, that the Earth is

surrounded by the stars and planets. Its usage here, in the introductory

lines, suggests that it is an accepted fact, included merely to further

illustrate the impressive nature of the Stoic universe. A few lines further

on, in his account of the creation of the universe, Manilius places the

Earth at the centre (1.168–70):

idcircoque manet stabilis, quia totus ab illo

tantundem refugit mundus fecitque cadendo

undique, ne caderet medium totius et imum.

The major description of the universe’s shape, however, is found later

(1.173–81), where Manilius augments his case with observational evidence,

examples and argument. He states that the planets and stars must circle

the Earth, alternately rising above and then setting below the horizon

every day, because otherwise the heavens would have a different

appearance. Manilius believed that this continual rising and setting could

occur only if the celestial bodies travelled under the Earth in the course of

each day (1.179ff.)

After explaining his belief as to the movement of the heavens, Manilius

dismisses two other theories. The first of these is that the heavens move

by ‘chance’, and the second, that the heavens are reborn every day (1.182–4):

nam neque fortuitos ortus surgentibus astris

nec totiens possum nascentem credere mundum

solisve assiduos partus et fata diurna,

As in his introduction to cosmology, the contending theories are only


superficially listed.180 In the subsequent lines (1.182-93), Manilius argues

superficially listed.180 In the subsequent lines (1.182-93), Manilius argues

against these theories by stating that the apparent regularity of the heavens

demonstrates the ‘ordered’ nature of the universe. This is in keeping with

Stoic doctrine, and the lines reflect Manilius’ use of astronomy as a tool

to explain the Stoic universe. This is essential for astrology, which requires

a predictable universe, and also for Stoicism which rests on the assumption

that the universe, as a whole, is controlled by and composed of one spirit.

Manilius constructs a coherent and consistent argument.

After his dismissal of rival explanations, Manilius continues his description

of the spherical universe, repeating and reinforcing some of the points

made earlier. In 1.194ff., he describes how the Sun moves unsupported

(i.e. without a ‘base’), maintaining its various meta— presumably referring

to the celestial circles described in 1.539–804.181 The Moon and stars are

also described as moving unsupported through the heavens in a similar

fashion to the Sun. The Earth itself is clearly placed at the centre of this

celestial sphere (1.202–3):

est igitur tellus mediam sortita cavernam

aeris, e toto pariter sublata profundo

After providing an observational and theoretical basis for the spherical

universe, the poem concludes with a Stoic justification (1.206–167).182 It

refers to a sphere as, haec est naturae facies (1.206) and continues by


180 Manilius’ account of cosmological theory takes place in 1.118–70.181 The precise meaning of this statement and of meta is unclear. Manilius could bereferring to the Sun’s path through the zodiac and thus to the points of the solsticeand equinox, or he could be referring to the celestial poles. He could also be usingmeta as a generic term for celestial ‘boundaries’—the limits of the paths the sevenplanets move through. Meta could also refer to the spheres the planets rotate around.It is likely, though, that Manilius is referring to a combination of all of thesecelestial reference points, as the general controlling points of the celestial sphere.182 Line 1.167 follows line 1.214.

stating that the sphere is the shape of the gods and thus perfect (1.211).

stating that the sphere is the shape of the gods and thus perfect (1.211).

These lines (1.173–214) present a well-argued justification for a spherical

universe. Observation, theory and Stoic philosophy are mixed in a skilful

fashion to this end, so that the accumulated astronomical thought of the

ancient world proves the Astronomica’s account of Stoicism. Once proven,

this belief becomes an axiom that is used in other areas of astrology and

Stoic thought found in the Astronomica.

Later in Book One this description of the structure of the universe is

repeated. After the account of the constellations (1.256–455) and prior to

an explanation of the celestial circles (1.539-804), the poem summarises

the movements of the heavens (1.532–808).183 The stars line the sky

(caelum laqueantia) with the Earth at the centre and the planets between.

Haec igitur texunt aequali sidera tractu

ignibus in varias caelum laqueantia formas.

altius his nihil est; haec sunt fastigia mundi;

publica naturae domus his contenta tenetur

finibus, amplectens pontum terrasque iacentis.

omnia concordi tractu veniuntque caduntque,

qua semel incubuit caelum versumque resurgit.

sunt alia adverso pugnantia sidera mundo,

quae terram caelumque inter volitantia pendent,

Saturni, Iovis et Martis Solisque, sub illis

Mercurius Venerem inter agit Lunamque volatus.

This is not the last account of the sphericity of the Earth or of the universe.


183 Eleven lines.

In what seems to be an attempt to add greater credence, Manilius provides

In what seems to be an attempt to add greater credence, Manilius provides

a little Euclidian geometry to prove the relative size of the heavens. In

1.539–56, we are effectively told that the Earth is two signs distant from

both the top and the bottom of the celestial sphere. This rests on the

Euclidian theorem (Elem. 4.15) that one side of a regular hexagon is

equal to the radius of a circle coincident with that hexagon. Thus the

radius of the Stoic universe is two signs.184

The relevance of these lines to the text is debatable, as they only marginally

relate to the discussion of the heavens taking place in Book One. A

clearer presentation of the same information would be a statement that the

Earth is one radius distant from the celestial sphere, so the inclusion of

these lines has been more of an indicator of Manilius’ mediocre level of

mathematical ability and knowledge, and of his use of ‘scientific’ material

to bolster his Stoicism than a useful addition to the account.185

In its entirety this account of sphericity seems to have been the standard

of the Stoics. Diogenes Laertius gives a brief description of Zeno’s

astronomy (7.144–6), referring to the stars and the earth as possessing

spherical shapes (7.145). Diogenes’ summary, however, does not dwell


184 To explain this in a more detailed fashion: Manilius is measuring the universe interms of the zodiac, which has twelve signs circling the sky—giving the sky acircumference of twelve signs. The diameter of a circle is 1/3 of its circumference(ignoring the slight inaccuracy of Pi equalling 3). As the circumference of thecelestial sphere is twelve signs, one third of this number is four signs, giving aradius of two signs. As Manilius notes, but does not correct, Pi is slightly greaterthan three.185 The universe is presented in a descriptive format, mathematics playing no part. Inthese few lines, Manilius departs from this style and describes one component of theuniverse in a mathematical fashion. Such an isolated example of mathematical modellingdoes not add to our understanding of the universe. What it does suggest is that Maniliusincluded this mathematical example as a device to impress his readers, which in turnsuggests that Manilius did not have a detailed grasp of mathematics.

on the innate superiority of this shape or its divine nature. Manilius on the

on the innate superiority of this shape or its divine nature. Manilius on the

other hand saw a reflection of God’s perfection in the shape of the heavens,

which both demonstrated the nature of God and also became one more

component of the structure of astrology.

3.2.3 The Spherical Shape of the Earth

Manilius regards the Earth as spherical and goes to some lengths to prove

this with examples scattered through the more general discussion of the

shape of the universe. It may be that he felt a specific need to demonstrate

the Earth’s ‘true nature’ because its perceived appearance is that of a flat

surface. Also, he may have reasoned that, if he could demonstrate the

sphericity of the Earth, then the rest of his argument concerning the

sphericity of the universe would be more easily believed.

The first of these is given in an explanation of Stoic cosmology, where

the Earth is described without qualification as glomerato pondere tellus

(1.159) and orbis (1.165). The first major account of the Earth’s shape is

found a few lines further on within the discussion of the constancy of the

universe. Manilius states that the Sun progressively lights different regions

of the Earth as it travels around the Earth in the course of each day

(1.189ff.). It is then stated that, as the observer apparently moves towards

the sunrise or the sunset, he or she actually moves further away from both

(1.192).186 This evidence is offered to the reader to prove that the Earth is

a sphere, which causes different regions to experience night and day at


186 These two lines are difficult to explain fully (1.192–3): semper et ulteriorvadentibus ortus ad ortum / occasumve obitus, caelum et cum sole perennet.This is correct in the case of the sunset. By moving west, the observer is movingtowards the sunset and, as the ‘line’ (the terminator) of sunset moves considerablyfaster than any human could, the sunset will always appear to move away. This is notthe case with sunrise. In moving east, the observer is moving in the opposite directionto the ‘line’ of sunrise; sunrise will arrive sooner.

different times. The poet then answers what must have been a common

different times. The poet then answers what must have been a common

objection—‘but the Earth is flat’. Manilius states that the ‘flat’ appearance

of the Earth is not its true shape: nec patulas distenta plagas (1.204) that

the Earth is a sphere, sed condita in orbem (1.204). This leads into a

discussion of the general shape of the universe (1.206–13), which concludes

by restating that the Earth is a sphere: sic tellus golmerata manet (1.214).

After providing a theoretical demonstration of the Earth’s sphericity,

Manilius then attempts to prove this argument by observational evidence.

He begins by stating that the entire sky is not visible from one location,

using the example of the southern star Canopus (approximately 53 degrees

south declination in A.D. 14), which is not visible north of the latitude of

Rhodes (36 degrees north) (1.216ff.).187 This does demonstrate, simply

and convincingly, the correct shape of the Earth. In a similar vein Manilius

continues that those who live in the far south will not see the northern

circumpolar constellations of the Bears: Ursa Major and Minor (1.218ff.).

Lunar eclipses are given as further evidence. First, the poem states that

Lunar eclipses, by displaying a round terrestrial shadow on the Moon’s

surface, demonstrate the sphericity of the Earth (1.221ff.) Secondly,

referring to the widespread visibility of a Lunar eclipse (1.228–35), Manilius

argues that if the Earth were flat, then the eclipsed Moon would rise at

one moment over the entire Earth. As it does not, then the Earth must be

spherical.188 This point is a practical example of the Earth’s sphericity

based upon the model described in 1.189ff. which describes the Sun’s

daily circling of the Earth. Manilius concludes his account with a repetition

of his claim that the Sun rises and sets at different times over different


187 These figures, after allowing a small variation for the height of the observer andrefraction, are correct. This observation, however, cannot be used in dating theAstronomica as Canopus was visible from a latitude equal to or south of that ofRhodes, for the entire Classical period.

areas of the Earth (1.236–47).

areas of the Earth (1.236–47).

The three pieces of evidence advanced by Manilius: the latitude of the

observer, the appearance and then the rising-time of the eclipsed Moon,


188 Manilius is referring to the apparent rising-time of the eclipsed Moon. This couldbe determined by reports of the Moon’s rising over the length of the Mediterraneanbasin. For example, (all measurements are made from the meridian of Greenwich) inthe eastern Mediterranean (30 degrees east) a fully eclipsed Moon may rise atsunset; however, in the middle Mediterranean (15 degrees east), the same Moonwould rise an hour later when the eclipse was partially over, while at the westernend of the Mediterranean (0 degrees east) the Moon would rise an hour later than inthe middle Mediterranean, in the last stages of eclipse. Thus, the varying level ofeclipse of the rising Moon would prove the Earth’s sphericity.

are each good arguments for the Earth’s sphericity.

are each good arguments for the Earth’s sphericity.

3.2.4 Suggestions of a Non-spherical Celestial Sphere

In the matter of celestial spheres, Manilius agrees with the general thrust

of ancient argument, but there are two lines in Book One which contradict

this conclusion. In 1.394, stars are said to be of different brightness, non

quod clara minus sed quod magis alta recedant. This statement runs

counter to others by Manilius that the stars are all on one celestial sphere

and are thus all equidistant from the Earth. The difficulty in interpreting

this line lies in its validity, since it is not found in all copies of the

manuscript, a fact that renders its usefulness questionable.189 There is one

other line that suggests the idea of relative distances and brightness. In

1.408, Sirius is vix sole minor, nisi quod procul haerens. Sirius is fainter

than the Sun merely because of its greater distance, not because it is

intrinsically fainter. This does not directly contradict the concept of the

stellar sphere, but it does suggest the idea of relative distance.

The belief that the stars varied in distance from the Earth is impossible to

reconcile with any other area of the Astronomica. Its inclusion does not

suggest that Manilius was pursuing an independent line of astronomical

inquiry, rather that he was preserving a tradition from an unknown source

(possibly Aristarchus of Samos). This, once again, demonstrates that

Manilius used a number of diverse sources and traditions without attempting

to reconcile them.

3.2.5 Conclusion

Without doubt, Manilius accepts the general opinion of Hellenistic science

___________________Astronomy - The Celestial Circles 118

189 Goold (1977) 34, n. a.

as to the geo-centric design of the heavens. This concept of the spherical

as to the geo-centric design of the heavens. This concept of the spherical

universe derived from several centuries of mathematical and astronomical

thought. All celestial bodies are spherical and move in circular paths

around the central, spherical Earth. This is the system within which Manilius

explains the remainder of his astronomical information and astrological

theory, yet he did not expect his audience to accept it without evidence.

His frequent use of observations and examples suggests some adherence

to observational science and the wish to prove to his readers his beliefs,

not merely ask them to believe by faith alone. Manilius’ discussion of the

spherical universe also demonstrates his holistic view of the universe:

there is a reason for everything and that reason is substantiated both by

Stoic thought and by observational evidence.


3.3 The Celestial Circles

3.3.1 Introduction

The appearance of the heavens at night (and to a lesser extent during the

day) is that of a vast, circular dome covering the Earth. While this appearance

is illusory, it is part of the basis for our conceptualisation of the night sky.

To measure and divide this sphere, the astronomers of antiquity projected

‘lines’, referred to as ‘celestial circles’, on to the sphere of the sky. These

circles vary in nature and cause, but each represents an astronomical

concept. Manilius provides an extensive list of celestial circles in Book

One, where he describes the circles in detail.190 Some of these circles, in

particular the zodiac, are then used in the later astrological Books to

convey astrological procedures.

The principal description of celestial circles is found in 1.565–717.

Unfortunately, there is a lacuna in the beginning of this section of an

estimated six lines.191 This leaves us without an introduction to Manilius’

list, though we still possess the bulk of the section. In his account, Manilius

describes all the significant circles–including the Milky Way (which is

not placed in that category by modern astronomy). His list describes the

five ‘parallel’ circles: the arctic, tropic of Cancer, the celestial equator,

the tropic of Capricorn and the antarctic circle. It continues with the

equinoctal colure and the solstitial colure. He lists the meridian, the horizon

and the zodiac, and concludes the section with a lengthy, mythical discussion

of the Milky Way. In summary, he describes a total of eleven circles.

This detailed account of celestial circles suggests a sound grasp of positional


190 A full description of celestial circles is found in Appendix A.191 Goold (1977) xxxii.

astronomy.192

astronomy.192

3.3.2 Manilius’ Celestial Circles

The following discussion will examine each of the circles described by

the poem. The first of the extant lines begins with a description of the five

‘parallel’ circles (1.566–602), so called, because these circles run parallel

to each other. Manilius begins with the arctic circle (1.566–7), lying 6

sexagesimal degrees (36 degrees)193 from the north celestial pole. This is

followed by the tropic of Cancer (1.568–74), lying 5 sexagesimal degrees

(30 degrees) from the arctic circle. Then Manilius reaches the centre of

the sky with the celestial equator (1.575–81), lying 4 sexagesimal degrees

(24 degrees) from the tropic of Cancer. This is followed by the tropic of

Capricorn (1.582–88), which lies 4 sexagesimal degrees (24 degrees)

from the celestial equator. Manilius then describes the antarctic circle

which lies 5 sexagesimal degrees (30 degrees) from the tropic of Capricorn

(1.591). Lastly, he indirectly refers to the existence of the south celestial

pole (1.592–3). Manilius correctly labels and places these circles, yet

there are a number of questions raised by their descriptions. He includes

no reference to his source(s), though he provides two clues as to their

origin: the use of the sexagesimal degree system and the provision of a

full complement of celestial circles.


192 It is difficult to date the development of the idea of celestial circles. Some, such asthe tropics, are more readily apparent and would have been discovered before moresubtle circles such as the colures. Neugebauer (1975) 3–4 suggests that it is reasonableto assume that by the time of Aristarchus (c. 310–250 B.C.) a full complement ofcelestial circle was present. It is possible that Eudoxus, the author of the firstmathematical model of the universe, either created or used the full range of circlesfound in the Astronomica.193 To avoid confusion, when the sexagesimal degree system is used it will be noted assuch, e.g. 6 sexagesimal degrees (= 36 ‘standard’ degrees). If there is no indicator,it should be assumed that the standard 360 degree system is in use.

To indicate the separation of the circles, Manilius gives a figure in degrees

measured against the background of the celestial sphere. In so doing, he

uses a system which contains only 60 degrees in a complete circle.194 This

usage runs counter to that found elsewhere in the Astronomica where

Manilius uses a system of 360 degrees.195

A reconstruction of the development of the degree system in the Greek

world suggests that the Greeks first referred to angles as fractions of other

angles: of a 90-degree quadrant, a fraction of a zodiacal sign (30 degrees)

or of a complete circle.196 Then c. 300–250 B.C. a 60–degree system was

adopted, as illustrated by Eratosthenes’ usage.197 The first known use of a

360-degree system were by the contemporaneous figures of Hipparchus

and Hypsicles, in the mid-second century B.C.198 The 60 and 360–degree

systems coexisted throughout the ancient era, with the sexagesimal system

falling into disuse only in the Byzantine era.199 This allows us to date

Manilius’ source for his account of the Celestial Circles to a period no

earlier than c. 300 B.C.


194 This is illustrated by his description of the separation of the Tropic of Cancer andthe celestial equator. Measured in a 360 degree system, the separation of these twocelestial circles is 24 degrees but Manilius lists it as only 4 degrees (1.575–81):tertius in media mundi regione locatus / ingenti spira totum praecingit Olympum /parte ab utraque videns axem, qua lumine Phoebus / componit paribus numerisnoctemque diemque / veris et autumni currens per tempora mixta, / cum mediumaequali distinguit limite caelum; / quattuor et gradibus sua fila reducit ab aestu.195 In Book Two, for example, when describing the zodiac, which completes a fullcircle through the sky, Manilius states that it covers 360 degrees, not 60 degrees(2.307–8): nam, cum sint partes orbis per signa trecentae / et ter vicenae, quasPhoebi circuit ardor.196 Dicks (1966) 27.197 Strabo Geog. 113–4, cf. Neugebauer (1975) 590ff.198 Hipparchus was the first known astronomer to use the 360 degree system. cf.Neugebauer (1975) 590ff. and Dicks (1977) 27–28.199 Neugebauer (1975) 591. Sextus Empiricus Ad. Astrol. 5.5–7 states that astrologersdivided a degree into 60 arc minutes. This level of accuracy is never approached byManilius.

The second clue as to the circles’ origin is found in the detailed list

Manilius gives. Hipparchus, in his Commentary on Aratus, states that

Eudoxus listed seven circles in his astronomy: the summer tropic, winter

tropic, the celestial equator, the solstitial and equinoctal colures, and the

arctic and antarctic circles.200 The Astronomica has all these plus the

additional circles of the meridian, the horizon, the Milky Way and the

zodiac. The presence of additional circles suggests a source later than

Eudoxus (mid-fourth century).

One additional piece of evidence lies in the description of the two tropics

as lying 4 sexagesimal degrees (24 degrees) from the celestial equator.

This figure is essentially correct, but the precise figure is slightly less.

The question is, why did Manilius not give a more accurate figure?201 The

figure of 24 degrees may have originated as early as the fifth century with

Oinopides of Chios.202 Geminius (? c. 70 B.C.) provides an account of the

celestial circles similar to Manilius, also enumerating them in the

sexagesimal system and giving an ecliptic obliquity of 4 degrees (24

degrees). Manilius was attempting here to give no more than an overview

of the state of the circles, so an approximate figure of 24 degrees was

adequate for his purpose.203

All we can conclude, based upon the number of circles and the use of the


200 Hipparchus Comm. 1.2.1, 10.1.11.201 Ptolemy, Alm. 1.12. Manilius was not averse to using fractions of a degree. In hisastrological writings he discusses measurements as small as 1/720 of a circle, halfof a degree (e.g. 3.275–300). Pannekoek (1961) 124 grants the 24 degree figure toEudoxus, and 23 degrees and 51 minutes of arc to Eratosthenes.202 Dicks (1970) 88, 157–8 suggests that Oinopedes (a contemporary of Anaxagoras)may have made the first crude determination of the obliquity of the equinox.203 Neugebauer (1975) 733–4 suggests that a figure of 24 degrees was used throughoutlater antiquity as a ‘round figure’ for the angle of the ecliptic.

sexagesimal system, is that Manilius ultimately relied on a source dated c.

sexagesimal system, is that Manilius ultimately relied on a source dated c.

300 B.C. or later.

A further question which arises from Manilius’ description of the five

parallel circles concerns his placement of the arctic and antarctic circles.

Manilius lists both as being 6 sexagesimal degrees from the pole, although

each has no intrinsic location.204 These circles are defined as arcs, circling

the celestial pole, which contain an area of sky that never sets. The

problem with this definition is that the diameter of this circle varies with

the observer’s latitude. As the observer approaches the pole, a larger area

of the sky never sets; as the observer moves away from the pole, a

smaller area remains above the horizon each day. The definition given by

Manilius—an Arctic and Antarctic circle drawn 36 degrees from the

pole—would result from an observation made from the 36th degree of

latitude.205

3.3.3 The Zodiac

The zodiac plays a central role in Manilius’ astrology. This is explicitly

stated in Book Three where the zodiac is referred to as the mundi praecordia

(3.61) and is granted dominance by nature (God), his regimen natura

dedit (3.64). This importance is not reflected in the discussion of the

zodiac in Book One, where the zodiac is the tenth circle in a list of


204 In comparison to the other three parallel circles that do have a fixed location.205 This corresponds to the latitude of Rhodes, which is associated with a number ofprominent figures, such as Panaetius, Posidonius, Hipparchus and Thrasyllus. It alsobears noting that this latitude also corresponds to that of northern Mesopotamia—thesource of some of Manilius’ astrology.Goold (1977) xxxii has made a minor error in listing the latitude of Rhodes as 54degrees north, rather than 36 degrees north. This is probably due to a confusion overRhodes’ true latitude and its reciprocal, which is used to calculate the location of thecelestial circle.

eleven. The circles are presented in a progressive fashion, with the position

eleven. The circles are presented in a progressive fashion, with the position

of each circle described in terms of its relationship to previously described

circles and constellations. The zodiac is described merely as bordered by

the constellations Crab and Capricorn and as intersecting the celestial

equator (1.672ff.).206 It is not granted any significance in the catalogue of

celestial circles.

This divergence between astrological importance and astronomical

insignificance can be explained if we assume that this section was based

upon an astronomical source that did not place great importance on the

zodiac and that Manilius used the source without serious modification.

3.3.4 The Precession of the Equinoxes

Two sections in the Astronomica reflect the achievements of Hipparchus

of Samos,207 one of these in a negative sense, since it concerns a significant

astronomical error found in the Astronomica, suggesting a pre-Hipparchian

level of astronomical knowledge. The two intersection-points of the celestial

equator (the projection of the Earth’s equator onto the sky) and the ecliptic,

(the annual path of the Sun) are important reference points in astronomy.

Prior to the time of Hipparchus, it was believed that these two points

were fixed, but Hipparchus proved that they were not, and that in fact

they slowly and regularly moved.208 His discovery of this phenomenon,

known as the ‘precession of the equinoxes’, was one of the great discoveries

of classical astronomy. In the Astronomica, however, the intersection


206 1.672 hunc tenet a summo Cancer, Capricornus ab imo, 1.675 sic per tris gyrosinflexus ducitur orbis.207 The role and importance of Hipparchus is discussed in ‘A History of Astronomy andAstrology’ (thesis section 1.2).208 For a full discussion of the ‘precession of the equinoxes’ see Appendix A. PtolemyAlm. 7.3, mentions Hipparchus’ discovery.

point is stated as fixed (1.275–84), and so Manilius does not recognise

point is stated as fixed (1.275–84), and so Manilius does not recognise

the existence of precession.

There are three possible reasons why Manilius did not use Hipparchus’

discovery. The first rests upon one component of Stoic dogma, the belief

that the universe was perfect and unchanging. Hipparchus’ precession of

the equinoxes, a constant varying of the heavens, suggests a less-than-

perfect universe that runs counter to Stoic belief. Secondly, there are a

number of mathematical statements in the Astronomica which suggest

that Manilius had only a limited grasp of mathematics.209 The calculation

of precession would, arguably, be the most complex mathematical task of

antiquity. While it seems likely that Manilius possessed some degree of

awareness of Hipparchus’ discovery, it is unlikely that he fully understood

or even wished to grasp its significance. Lastly, there is a statement

attributed to Hipparchus by Ptolemy, to the effect that Hipparchus did not

believe that the current state of astronomical knowledge was sufficient to

devise a valid model of the solar system.210 Such a statement would not

be well regarded by an astrologer whose understanding of astrological

divination was based upon the assumption that the universe could be, and

was, understood.

From Manilius’ perspective Hipparchus was not a suitable source for

astronomical thought. Also precession was rarely mentioned in later

astronomical writings, since it was a difficult concept. This suggests that

Manilius did not rely on the most up-to-date astronomical theories, but

upon earlier and possibly simpler, Stoic sources.


209 See thesis section 2.2.5, which deals with Manilius as an mathematician, for a fulldiscussion of this point.210 Ptolemy Alma. 9.2.

3.3.5 The Location of the Colure Points

As the Sun moves along the ecliptic (its path through the sky) in the

course of each year, the Earth experiences variations in the length of day

and night. These are the result of the 23.5 degree apparent ‘swing’ north

and south of the equator by the Sun. This movement has four defining

points. The first two of which are the points at which the Sun crosses the

celestial equator, occurring in the constellations of Libra and Aries. When

the Sun reaches these points, the Earth experiences days and nights of

equal length. These periods of time are known as the equinoxes and their

positions on the celestial equator are referred to as the equinoctal points.

The arc drawn between these points and the celestial poles is the equinoctal

colure.

The second two of the defining points of the Sun’s annual movement

occur when the Sun reaches the extreme north and south points in its

journey along the ecliptic, occurring in the constellations of Capricorn

and Cancer. In the northern hemisphere, when the Sun enters Cancer, the

longest day and shortest night occur. The opposite is true for the southern

hemisphere. These events are known as the solstices and these two positions

on the celestial equator are referred to as the solstitial points. As with the

equinoctal points, there is a celestial circle that runs through these two

points and the celestial poles, which is called the solstitial colure. Manilius

includes the equinoctal and solstitial circles in his tally of celestial circles.

These points have a definite location in the sky in relation to the celestial

equator and the ecliptic. The question that arises concerns their location

with reference to the zodiacal constellations. In the main, Manilius places

these colure points at the beginning (the first degree) of the relevant


constellations but there are indications that he sometimes placed them

constellations but there are indications that he sometimes placed them

within the constellations.

First, let us look at the three references that suggest the use of the first

degree. The primary placement of the equinoctal and solstitial colures

describes the location of these circles via the constellations.(1.610ff.) The

first equinoctal point is placed on the boundary of Libra: ...dividit Arctos /

et iuga Chelarum medio volitantia gyro (1.610–1); and the second on the

border of Aries: Lanigerique notat fines clarumque Trigonum (1.615).

This last reference clearly indicates that the border of the constellation

lies on the equinoctal point.

In lines 2.178ff. Manilius describes the tropical signs as: Aries, Libra,

Cancer and Capricorn 2.178–9.211

idcirco tropicis praecedunt omnibus astra

bina, ut Lanigero, Chelis Cancroque Caproque,212

These lines clearly identify the boundaries of the constellations as the

indicators of the tropic and equinoctal points. This is also the definition

assumed in lines 3.278–93, where Manilius discusses the rising of the

signs (zodiacal constellations) and in 3.395ff. and 3.443ff., and where the

varying length of the day is discussed. While none of these latter examples

specifically states that the colure points lie at the beginning of the

constellations, it is implied.


211 Line 2.177 seems to indicate that the change of season begins in the middle of theconstellation incipit autumnus media sub Virgine utrimque. This could simply be apoor choice of phrase on Manilius’ part.212 It should be mentioned here that Manilius’ use of the term ‘tropic’ (tropicis2.178) is technically inaccurate. The signs described are both the tropic and equinoctal,but, Manilius may have used the term ‘tropic’ as a generic term for these fourpoints.

Lastly, in a discussion of the effects of the zodiacal constellations, Manilius

assigns each to its respective season. In doing this, he again confirms the

location of the colure points as lying at the beginning of each constellation

(2.266–9):

aestas a Geminis, autumnus Virgine surgit,

bruma Sagittifero, ver Piscibus incipit esse,

quattuor in partes scribuntur sidera terna;


hiberna aestivis, autumni verna repugnant.

hiberna aestivis, autumni verna repugnant.

This passage is best displayed in the following table.

Table 3

Seasons Ascribed to Zodiacal Constellations: 2.266–9

___________________________________

Spring Summer Autumn Winter

Pisces Gemini Virgo Sagittarius

Aries Cancer Libra Capricorn

Taurus Leo Scorpio Aquarius

___________________________________

The above three references would seem to indicate that Manilius used the

first degree as the indicator of the colures, but in two other references the

colure points are found elsewhere. The first of these is part of an extended

discussion that consumes approximately one half of Book Three, in which

Manilius explains various methods of deriving the rising-times of the

zodiacal constellations (3.203–504). The reference states that the shortest

day in the northern hemisphere occurs when the Sun is in the eighth

degree of the constellation Capricorn, fulget in octava Capricorni parte

biformis (3.257). The reference to the eighth degree differs from that

implied in other parts of this same discussion. For example, the indicator

of equal days and nights is given as Libra ...in Libra cum lucem vincere

noctes (3.252); summer is reached (with the longest day in the northern

hemisphere) when the Sun is in Cancer ...ad ardentis pugnarunt sidera


Cancri (3.264). Thus the reference to the eighth degrees is unique, even

Cancri (3.264). Thus the reference to the eighth degrees is unique, even

contradictory, within its own context.

The second and last reference to the colure points lying other than in the

first degree is in the last lines of Book Three.213 Here Manilius refers to a

range of opinion (reflecting a range of sources and traditions) as to where

the colure points may be placed, whether in the eighth, tenth or also the

first degree of the constellation (3.680–2):

has quidam vires octava in parte reponunt ;

sunt quibus esse placet decimae; nec defuit auctor

qui primae momenta daret frenosque dierum.

This discussion illustrates again the diversity of sources at Manilius’

fingertips and the ease with which he combined these sources with no

comprehensive attempt at reconciliation. His statement that the winter

solstitial point occurs at the eighth degree of Capricorn is an anomaly

(3.257). It may have been an error on his part, but it is more likely that

Manilius simply did not care.


213 There are two other references to the placement of the colure points. In the firstof these, Manilius places the longest day in Cancer (3.625–7) Cancer ad aestivaefulget fastigia zonae / extenditque diem summum parvoque recessu / destruit et,quanto fraudavit tempore luces. In the following reference, the shortest (northern)day occurs when the Sun is in Capricorn (3.637–9) Parte ex adversa brumamCapricornus inertem / per minimas cogit luces et maxima noctis / tempora, producitquediem tenebrasque resolvit.Both of these descriptions are correct, but there is nothing in either reference toindicate where Manilius placed the Sun. It could lie at the mid-point or at the firstdegree of the constellation. As other references are similarly vague about the exactlocation of the colure points (3.278–93, 3.395–436 and 3.443–82), there is littlereason to assume that in these later references they occur elsewhere than at the firstdegree. If this is the case, then the only clear reference to other than the first degreeis in 3.257 and in the end of Book Three.

3.3.6 Conclusion

Manilius provided a full and comprehensive account of the celestial circles

known to ancient astronomy. His only major omission was the precession

of the equinoxes. The evidence suggests that Manilius’ source is later

than c. 300 B.C., and was astronomical, not astrological.

The format of this account also provides an insight into Manilius’ goal.

His full account of the circles contained more than was needed for an

understanding of the astrological theories found in the Astronomica. It

would have been possible to edit this into an astrological framework and

provide only that information necessary for astrology, but this Manilius

does not do. He is content merely to copy an account of the celestial

circles from an astronomical source without modification. Manilius is not

concerned with providing a correct account, which could be used as the

basis of his work. The Astronomica reflects a diversity of sources with

little attempt at reconciliation; Manilius’ exposition of the celestial circles

is typical of this approach.

___________________Astronomy - The Constellations 132

3.4 Constellations

3.4.1 Introduction

The constellations are groupings of the stars into recognisable ‘patterns’.

The precise origin of many of the constellations is not known but the

majority of the modern constellations derived from a combination of

Babylonian and Greek traditions.214 The motivating idea for many

constellations is indicated by their name (e.g. Canis Major and Draco).

Other constellations were named for myth and religion (e.g. Perseus and

Andromeda) while others have a more mundane origin (e.g. Eridanus).

The function of constellations in astronomy (apart from their aesthetic

role) is to identify stars (e.g. Alpha Libra—the brightest star in Libra). In

the field of astrology, however, constellations in themselves are believed

to possess influence over human destiny.

In Book One, Manilius includes a constellation catalogue, and its inclusion

raises two issues which deserve further examination. The first of these is

its bias, since although the catalogue is comprehensive, it clearly reflects

an astrological orientation. The second issue is the relevance of the catalogue

to the text. Manilius’ astrology relies upon the zodiac, and so the non-

zodiacal constellations are irrelevant, yet the catalogue includes a near

full list of constellations.215


214 For a discussion of the origins and history of the constellations see Allen (1963)(a discussion of the origin of each constellation forms the introduction to the descriptionof the constellation).215 Book Five uses non-zodiacal constellations in astrology. The astrology of Book Fiveis fundamentally different from that found in the first four Books.



The constellation catalogue in the Astronomica (1.255–531) is a descriptive

catalogue, in that the position of the stars and constellations are described

in a pictorial form. This differs from the description of celestial circles

(1.539–804), where a coordinate system based upon angular separation

measured in degrees is used. The earliest known constellation catalogue

is that of Eudoxus, and from its account in Hipparchus’ commentary, it

too was a descriptive catalogue, similar to the surviving catalogue of

Aratus. It was probably Hipparchus who first created a coordinate

catalogue,216 but the only surviving example of such a coordinate catalogue

is found in Ptolemy’s Almagest. Manilius’ decision to follow Eudoxus’

model and not that of Hipparchus most probably reflects the relative ease

of turning a descriptive account into poetry as opposed to the obvious

difficulty of converting tabular, numerical information into verse. The

poet was probably also influenced by his previously mentioned avoidance

of Hipparchus’ work. Manilius’ catalogue also contains a large amount of

‘myth’, describing, for example, the legend of Jupiter and Leda (1.337-40).

This suggests a poetic or astrological origin for the catalogue as opposed

to the more ‘scientific’ origin of the catalogue of celestial circles.

The constellation catalogue is divided into three parts. The first and smallest

is an account of the zodiacal constellations (1.263–274), beginning with

Aries and listing the constellations in an easterly direction. Aries was

presumably chosen as the starting point as it contained the equinox in

Manilius’ era. The second part of the catalogue describes the constellations

lying to the north of the zodiac (1.294–370). These begin with Ursa

Major, move south-westerly to the zodiac and then easterly, concluding


216 There is some controversy as to whether Hipparchus or Ptolemy created thecoordinate system. This question is discussed in the section of this chapter on StellarMagnitudes (thesis section 3.6).

with Heniochus (Auriga). The last part contains the constellations lying to

with Heniochus (Auriga). The last part contains the constellations lying to

the south of the zodiac (1.387–442). This description begins with Orion,

moves south, circling the unseen region surrounding the south celestial

pole, then turns to a easterly direction, concluding with Flumina (Eridanus).

The catalogue contains 19 northern and 13 southern constellations, which,

combined with the 12 zodiacal constellations, give Manilius a total of 44

constellations.

Manilius’ catalogue reflects his appreciation of the zodiac. In the lines

preceding his catalogue, he states that the zodiac is the indicator of fate: e

quibus et ratio fatorum ducitur omnis (1.261). Also, he claims that the

zodiac holds the heavens together, ut sit idem mundi primum quod continet

arcem (1.262). The zodiac was all important to Manilius and he thus used

it as the starting point for his explanation of the constellations. His decision

to list the zodiac as a separate group in the catalogue and to use the

zodiac as the divider of northern and southern constellations differs from

some earlier catalogues. Aratus used the zodiac to divide the sky into two

groups, north and south, without listing the zodiac as a distinct group.217

Ptolemy’s decision, with regard to the placement of the zodiac, is a mixture

of both systems.218


217 Aratus’ first and northern constellation group (Phaen. 26–318) includes theentire zodiac and all of the constellations north of the zodiac. His southern group(Phaen. 322–450) are the remaining constellations found south of the zodiac. Inlines 319–21, Aratus states that he uses the Sun’s path (the ecliptic) as the dividerbetween the two groups of constellations. Thus, Aratus recognises the existence of thezodiac but not as a group of constellations, rather in an astronomical sense as thepath of the Sun. He does not grant significance to the zodiacal constellations themselves.Aratus is examined in detail in 1.4.2.218 Ptolemy’s catalogue begins with the northern constellations at the end of BookSeven and concludes, in the beginning of Book Eight, with a catalogue of southernconstellations. The zodiac is divided between these two categories, but the northernhalf of the zodiac lies at the end of the northern catalogue and the southern half at thebeginning of the southern catalogue. Thus Ptolemy both divides the sky at the celestialequator and recognises the zodiac as a divider between north and south.

There may well have been two traditions in the construction of constellation

catalogues, one reflecting an astrological tradition, the other an astronomical

tradition. The difference between the two meant more than the choice of a

different divider, since the placement of approximately one quarter of the

constellations had to be changed.219 As a guide to the catalogue Manilius’

constellations are listed, along with Aratus’, in appendix B in the order

found in the Astronomica.

3.4.3 Anomalies in Manilius’ Catalogue

Manilius’ catalogue is a comprehensive but not complete account of the

constellations known in the ancient world. It is the ‘omitted’ constellations,

Coma Bernices, Corona Australis, Equuleus and Lupus, that provide clues

as to Manilius’ sources (an potentially, as to his intent in writing the

poem).

The first of these, Coma Bernices,220 is a small and faint constellation to

the east of Leo. Aratus (writing prior to its naming) alluded to this group

of stars in the Phaenomena (146), which suggests that the stars had a

recognisable existence and symmetry.221 Nevertheless, even after the naming

of the constellation, it was not always acknowledged until the Renaissance.222

The second ‘missing’ constellation is Corona Australis, a constellation


219 See Goold (1977) xxiv–xxxi.220 It was named after Berenice, the wife of the 3rd Ptolemy, Euergetes, c. 245 B.C.The third century B.C. mathematician and astronomer Conon is credited with thecreation of this constellation, Allen (1963) 168–9.221 The visual image of the constellation is not impressive. Its brightest star is onlyof 4th magnitude, nor is it prominent in any other fashion, thus its late creation isnot surprising. There is also a strong possibility that its creation had politicalmotives. The prestige of the Ptolemaic dynasty would be reflected in the heavens bythis new constellation.222 Allen (1963) 168ff. lists Eratosthenes, Geminus, Hyginus, Pliny and Ptolemy asauthors who referred to the constellation.

found south of Sagittarius. Neither Aratus nor Vitruvius mention this

found south of Sagittarius. Neither Aratus nor Vitruvius mention this

constellation, but it was known to Ptolemy who includes it in his list of

constellations of the southern hemisphere (Book Eight). It is possible that

Manilius’ omission of this constellation simply reflects its insignificance

or, equally possibly, its lack of wide-spread recognition prior to Ptolemys’

era. The third constellation is Equuleus, a small and faint grouping west

of Pegasus. Geminus (3.8) states that it was named by Hipparchus, a

century and a half prior to Manilius.223 It was not included in the catalogues

of Aratus, Hyginus or Vitruvius, yet Ptolemy includes it in his list of

constellations of the northern hemisphere. The last of the missing four is

the constellation Lupus, a faint, small constellation located next to

Centaurus, between Ara and Scorpius. It is pictured as a small animal

held by Centaurus. Aratus includes it in his catalogue (442) as dies Vitruvius

(9.5.1) (Aratus’ listing of this constellation suggests that it was well known),

and as Goold suggests (xxx), Manilius could have considered this

constellation as an intrinsic part of the constellation Centaurus.

The omission by Manilius of these four constellations could be due to no

more than their faintness and insignificance, yet Manilius does include

other small and faint constellations in the catalogue (e.g. Sagitta, Triangulum

and Crater, although all of these are somewhat more distinctive than the

four missing constellations). The exclusion of these constellations, all

perhaps known in the time of Manilius, suggests both a neglect of minor

constellations and a reliance on earlier sources, possibly from the early

third century. In this Manilius seems to have ignored Hipparchus’ stellar

catalogue and its successors. There is also the possibility that the ommission

of these constellations is due, as with other aspects of the work, to an


223 Geminus wrote an Introduction to Astronomy. The date of Geminus is an unresolvedquestion. Neugebauer (1975) 578ff. gives a date of c. A.D. 50. This is one, smalladditional piece of evidence that Manilius did not use Hipparchus as a source.

indifference to minor details.

indifference to minor details.

3.4.4 Conclusion

Manilius’ catalogue is a comprehensive and well-presented summary of

the constellations known in the ancient world. It clearly possesses an

astrological orientation, indicated by the prominent role assigned to the

zodiac. The date of the sources of the catalogue is impossible to determine

precisely, but a date in the third century is likely. As with much of

Manilius’ astronomical information, its utility is questionable. Apart from

Book Five, Manilius concentrates his astrological attention solely on the

zodiac and there is no need for this level of information on the non-zodiacal

constellations.

___________________Astronomy - The Planets 138

3.5. The Planets

3.5.1 Introduction

The Earth is surrounded by ‘fixed’ stars, so named as they remain in

fixed positions in the sky. Against the backdrop of these stars move the

five planets visible to the naked eye, and the Sun and the Moon. The

planets move amongst the stars in slow but complex patterns, while the

Sun and the Moon share the distinction of an obvious, circular shape and

unidirectional motion. Manilius recognises the existence of the planets

and provides two essentially identical lists (1.807–808224 and 5.6–7),

including the Sun and the Moon in his tally. He briefly outlines their

nature as follows (1.807–808):

Saturni, Iovis et Martis Solisque, sub illis

Mercurius Venerem inter agit Lunamque volatus.225

This description follows the geo-centric model used in Greek astronomy.

In their travels around the Earth, the planets keep to a narrow band of sky

known as the zodiac.226 It is, however, very difficult to reconcile observation

of the complex heliocentric movement of the planets with predictions

based on a geo-centric model.227


224 Housman moved 1.805–8 to 1.538.225 It should be noted that 1.807 is identical with 5.6.226 The planets orbit around the Sun in a near ‘flat’ plane. As such, as viewed from theEarth, the planets appear to move along the sky in a narrow path, the zodiac. Inreality, the planets do not share an identical plane; some are angled ‘above’ and‘below’ the average. This added complexity of planetary motion made the task ofpredicting the planets’ movement more difficult.227 The observed motion of the planets is discussed later in thesis section (2.5.3).

3.5.2 The Order of the Planets

Manilius lists the seven planets in their correct sidereal order (the duration

of the orbital period of each planet). The order given in 1.807–808 and

repeated in 5.6–7 228, begins with the planet Saturn, the planet most distant

from the Earth, followed by Jupiter, Mars, the Sun, then Venus, Mercury,

and lastly the Moon. The time taken for each planet to circle the Earth

was held (not altogether incorrectly) to be its relative distance from the

Earth.

This description of the planets indicates that Manilius knew the astronomical

theories of his day, since his planetary order reflects a knowledge of

astronomy defined only in the fourth century B.C. by Eudoxus and

confirmed by Hipparchus in the second century.229 The planetary order

given in earlier periods varied,230 and it would seem that the Greeks did

not recognise the existence of the planets as clearly distinct from the

fixed stars until the fifth century.231

Manilius’ description omits an account of the orbital periods of the planets,


228 There is a lacuna in Book Five, which Goold (1977) xcvii–c believes described theastrological significance of the planets. This astrological account may have included,as background material, additional astronomical information.229 Dicks (1970) 153.230 Plato linked the inferior planets, Mercury and Venus, with the Sun’s annualmotion (Timaeus 38).The Egyptians most often used the order: Jupiter, Saturn, Mars, Mercury and VenusOld Babylonian order: Jupiter, Venus, Saturn, Mercury and Mars.New Babylonian order (Persian/Hellenistic period): Jupiter, Mars, Venus, Mercuryand Saturn.cf. Neugebauer (1975) 690–2.231 Dicks (1970) 30 provides a brief discussion of this point. Plato, when describingthe planets in Timaeus 38, recognises their circular motion but provides no definiteinformation about the orbital period or position.232 It is difficult to determine when the Greeks measured the orbital periods of theplanets, but, by the time of Eudoxus, they must have been known, as they wereessential to his planetary theory.

facts known in his day.232 Since he is willing to include numbers in the

facts known in his day.232 Since he is willing to include numbers in the

Astronomica when circumstances call for them (astrological discussions

sometimes revolve around measures as small as 0.5 degrees), the omission

of the sidereal period may reflect Manilius’ lack of interest in the planets.

3.5.3 Retrograde Planetary Motion

Because the Sun (and not the Earth) lies at the centre of the solar system,

and the Earth itself is merely one of five (visible) planets orbiting the

Sun, the path of the planets in the sky appears complex. Over the course

of a year the planets move eastwards, slow, halt, and then move westwards,

halt again and then loop back over their previous courses, progressively

moving westwards. The exact movement of each planet varies due to its

distance from the Sun and its orbital variability. The ‘backward’ motion

of the planets is referred to as ‘retrograde motion’. Any attempt to explain

this behaviour in terms of a geo-centric solar system is understandably

difficult and was a task that consumed much of the energy of ancient

astronomy.233

Manilius was aware of the existence of retrograde motion. He describes

the planets as ‘struggling’ against the background stars (1.15):234 ...stellarum

noscere cursus, a clear depiction of the retrograde motion of the planets

as they move with, then against, and at varying speeds with respect to the

background stars. Manilius, however, makes no attempt to explain

retrograde motion. In his era, there was a large body of work that explained


233 Each successive era of ancient astronomy, concluding with Ptolemy, created evermore complex models in an attempt to portray the motion of the planets accurately,but none of these was entirely successful.234 Also: 1.309 per bis sena volant contra nitentia signa, 1.805 (following line1.538) sunt alia adverso pugnantia sidera mundo, 1.670 et quinque adverso luctantiasidera mundo, 5.1-2 ... signisque relatis / quis adversa meant stellarum numinaquinque

the phenomenon by postulating an ever increasing number of conjoint

the phenomenon by postulating an ever increasing number of conjoint

spheres upon which each planet moved. Manilius’ omission probably

stems from his desire to provide only an overview of astronomy to his

readers. A discussion of planetary astronomical theory would be a

challenging and time-consuming task. It is also possible that, as this

theory was complex and depended upon a knowledge of mathematics,

Manilius, who nowhere demonstrates a grasp of advanced mathematics,

may have felt the task beyond him.

The motion of the Sun and Moon differs from that of the five true planets

in that they do not undergo retrograde motion, but rather they move in

uninterrupted paths around the Earth. Manilius distinguishes between these

two groups of ‘planets’. In 3.62–3, the Sun and Moon are distinguished

from the ‘wandering stars’:

disposita, obtineant, Phoebum Lunamque vagasque

evincunt stellas nec non vincuntur et ipsa,

This distinction of the Sun and Moon is repeated in 5.2–3, where Manilius

lists the planets for the second time:

quis adversa meant stellarum numina quinque

quadriiugis et Phoebus equis et Delia bigis

In these references, Manilius clearly divides the seven ‘planets’ into two

groups based on the criterion of retrograde motion. He also indicates an

awareness of a further division of the planets. In modern astronomy the

five ‘true’ planets are divided into two categories by their orbital position:

those lying further from the Sun than the Earth (Saturn, Jupiter and Mars)

are known as the ‘superior’ planets; and those closer (Venus and Mercury)


are referred to as the ‘inferior’ planets. Both groups display some form of

are referred to as the ‘inferior’ planets. Both groups display some form of

retrograde motion. The superior planets display a more complex form as

they orbit around the entire sky, while the inferior planets display a far

simpler variation and never move far from the Sun. Although, by the time

of Manilius these two forms of retrograde motion had been recognised,

he does not clearly differentiate the two categories, although he does

make two references which indicate the difference. In 1.871–3, within his

account of comets and meteors Manilius refers to Mercury and Venus

merging into the Sun’s light and then reappearing:

ac modo dimittit, sicut Cyllenius orbis

et Venus, accenso cum ducit vespere noctem

saepe latent falluntque oculos rursusque revisunt;

His reference to the two inferior planets recognises their unique movement.

Similarly, a recognition of the orbital difference between the inferior and

superior planets is found in the statement that Venus is an evening and

morning star (1.177–8):

nec matutinis fulgeret Lucifer horis,

Hesperos emenso dederat qui lumen Olympo.235

This reference implies that Venus, unlike the superior planets, could be

only a morning or an evening star. It could never travel far from the Sun.


235 Seneca makes a statement on this point, claiming that successive ages uncovermore of the mysteries of the heavens and that the knowledge of planetary movement,retrograde motion and morning and evening stars, had only been discovered relativelyrecently (NQ. 7.25.5). As Seneca apparently believed that astrological researchstretched back thousands of years ‘relatively recently’ could refer to the Hellenisticera, a mere three centuries in the past.

3.5.4 Conclusion

3.5.4 Conclusion

Manilius’ extant accounts of the planets amount to no more than a few

lines scattered throughout the Astronomica. These lines provide a reasonable

summary of planetary behaviour while avoiding complex or mathematical

discussion. Manilius lists the planets in correct sidereal order but their

orbital periods are not given. He describes planetary retrograde motion

but provides no discussion of its cause or variants. It is clear that, even

though a theory of planetary motion had been in existence for two centuries,

Manilius saw the planets as of little importance in his schema and, therefore,

they received little attention from him.236

___________________Astronomy - Stellar Magnitudes 144

236 His interest in planets should be compared to his account of comets and meteors atthe end of Book One. This runs to over a hundred lines, but Manilius does not makeuse of this knowledge in the subsequent text.

3.6 Stellar Magnitude

3.6.1 Introduction

The stars in the night sky vary in brightness. In order to categorise the

different levels of brightness, a system was devised in antiquity that is

still in use today (with modifications). This is the stellar ‘magnitude’

system in which there are six categories of brightness each termed

‘magnitude’. The brightest stars in the heavens are of the first magnitude

while the faintest stars visible to the human eye are of the sixth. The

creator of this system is believed to have been Hipparchus of Samos.237 It

is believed that the magnitude system formed part of his stellar catalogue,

but, this is not certain. Regrettably, his catalogue has not survived, and

we must rely on fragments and the stellar catalogue in the Almagest. A

suspicion exists that Ptolemy was the creator of the magnitude system,

but Manilius’ use of the magnitude system predates Ptolemy’s and provides

evidence as to its earlier date, since the stellar magnitude system is preserved

in Book Five of the Astronomica.

3.6.2 Manilius’ Text

In 5.710–7 (with an estimated initial 30 lines missing) Manilius lists the


237 A key reference is from Pliny the younger, who states in Nat. Hist. 2.95:(Hipparchus) adnumerare posteris stellas ac sidera ad nomen expungere organisexcogitatus, per quae singularum loca atque magnitudines signaret. As Pliny died (c.A.D 112) a generation prior to Ptolemy’s birth (c. A.D. 127) his reference toHipparchian ‘magnitudes’ does suggest that the concept predated Ptolemy.The suggestion that Hipparchus did not create the magnitude system is based on theabsence of any specific mention of the stellar magnitude in Hipparchus’ commentaryon Aratus and Eudoxus, Neugebauer (1975) 291–2, 277–88. This is not conclusive,as the commentary could have been written earlier in Hipparchus’ career. This issuggested by Dicks (1970) 162–3.

constellations in their order of relative brightness, using Hipparchus’

constellations in their order of relative brightness, using Hipparchus’

magnitude system.238 The surviving lines, which list the constellations of

the third to sixth magnitude, are enough to indicate that Manilius categorised

the constellations into six orders of brightness, beginning with the first

magnitude. What is noteworthy, however, is their lack of relevance to the

text. They are found at the end of the work and are unrelated to any

section of astrological theory found in the Astronomica. Their only relevance

is to the lines immediately following (5.734–42, the concluding lines of

Book Five), that describe the social hierarchy of the Roman state and

compare it to the hierarchy of stellar magnitudes.239 Thus, the constellation

magnitude catalogue is used as a metaphor that grants divine approval

upon the social structure of Rome. Cicero mentions that the Stoics used

the metaphor of a city as a model of the world (de Fin. 3.63).240 As these

lines are the earliest extant expression of a magnitude system, they deserve

examination.

3.6.3 Constellations v. Stars v. Brightness

The first point to make about the constellation magnitude catalogue is its

format—the cataloguing of constellations by magnitude. Ptolemy’s, and

presumably Hipparchus’ magnitude system described the magnitude of


238 5.710–7 tertia Pleiadas dotavit forma sorores / femineum rubro vultum suffusapyropo / invenitque parem sub te, Cynosura, colorem, / et quos Delphinus iaculaturquattuor ignes / Deltotonque tribus facibus, similique nitentem / luce Aquilam etflexos per lubrica terga dracones / tum quartum sextumque genus discernitur omni /e numero, summamque gradus qui iungit utramque.239 It is possible, though there is no indication of it in any extant source, that theconstellation magnitude system played a role in the ease of identifying constellations.A constellation could be referred to as ‘bright’ or ‘faint’ but with this system itwould be possible to indicate its relative brightness directly.240 Schofield (1991) devotes an entire monograph to discussing the Stoic ‘cosmiccity’. A detailed discussion of its usage is not called for here. Essentially, the Stoicssaw the cosmic order reflected in the order of the city. The details varied widelybetween different Stoics and different eras.

stars, not of constellations. As a general distinction, constellations are

stars, not of constellations. As a general distinction, constellations are

central to astrology, while stars are central to astronomy.241 This suggests

an astrological, not an astronomical source for Manilius’ catalogue.242 It

would be reasonable to conclude that an astrologer, somewhere in the

century and a half between Hipparchus and Manilius, devised a magnitude

system for constellations based on the Hipparchus’ stellar magnitude

system.243

There is also the question of the lack of relevance of this catalogue to

astrology. It is a constellation’s position that determines its astrological

influence, not its brightness. Nowhere in the Astronomica does Manilius

refer to the brightness of a constellation as a factor of its astrological

significance, and the catalogue becomes less relevant because of the

inclusion of non-zodiacal constellations. The zodiac is central to Manilius’

astrology; but only in Book Five, with the description of the rising and

setting of non-zodiacal constellations, is this challenged. What the catalogue

does indicate is the relationship between astrology and astronomy. There

is a question in the study of these two disciplines as to their origins and

relative primacy. I believe, that the inclusion of these lines discussing


241 Astrology revolved around the zodiacal constellations and the planets. Predictionswere made on the basis of their changing relationships, and individual stars playedonly a small role in astrology. As opposed to this, astronomers relied on accuratemeasurements of the positions of individual stars and planets. For example, Hipparchus’discovery of the precession of the equinoxes relied on a very large number of accuratestellar observations. During the course of the development of astronomy, constellationswould have become mere labels for the stars they contained.242 There is a suggestion from some ancient sources that Hipparchus was an astrologeras well as an astronomer. As such, there is a possibility that Hipparchus producedboth a stellar and constellation magnitude system. While this is possible, there is nosupport for this in any reliable source. Also Neugebauer (1975) 331–2 denouncesthe belief that Hipparchus was an astrologer.243 One could ask ‘why might this hypothetical astrologer not be Manilius?’ If, however,the author of this system were Manilius, it would be reasonable to assume that itwould occupy a far larger and more significant position in the Astronomica than itdoes.

constellation magnitudes in a work of astrology sheds some light on this

constellation magnitudes in a work of astrology sheds some light on this

question.

In devising a constellation magnitude system and including it in a work

of astrology, astrologers in general, and Manilius in particular, were copying

an astronomical procedure. This suggests a degree of intellectual

dependence of astrology on astronomy. The existence of the catalogue

also suggests (or confirms) the existence of a large body of astrological

literature. Considering the popularity of astrology in the Hellenistic world

and even more so in the Roman, the latter is not a surprising finding.

3.6.4 Hipparchus, Ptolemy and the Stellar Catalogue

As mentioned earlier, the authorship of the first positional stellar catalogue,

in which the stars are individually located by a coordinate system, is in

dispute.244 Both Hipparchus and Ptolemy are credited with such a catalogue.

The debate revolves around two questions: the question as to the worth of

Hipparchus’ catalogue as compared to Ptolemy’s and, assuming that

Hipparchus’ catalogue was of sufficient quality, the dependence of

Ptolemy’s catalogue upon that of Hipparchus. The presence of the

magnitude system in the Astronomica provides evidence that Hipparchus

was the author of a ‘positional’ stellar catalogue. The Astronomica contains

no discernible evidence on the second question.

To answer the question as to the quality of Hipparchus’ catalogue, we can

take as a starting point his recognised mathematical ability and his dedication

to his research. The fact of discovery of the precession of the equinoxes

alone suggests this.


244 Neugebauer (1975) 275ff., cf. the introduction to the Teubner edition of theAlmagest, Newton (1977) 10-25, Riley (1995).

This fact also constitutes the first link in a chain of evidence to suggest

that Hipparchus created the first stellar catalogue. The calculations

revealing precession would also require accurate measurements of the

position of the planets and the Moon. This, in turn, would require an

accurate knowledge of the position of a number of reference stars, from

which the changing position of the planets and Moon could be measured.

As the planets, in their movement through the zodiac, cover the entire

circumference of the sky, a range of reference stars spanning a significant

percentage of the sky would be required to measure their movement.245

Thus, the means by which Hipparchus carried out his observations of the

planets formed the basis for a stellar catalogue in itself.

The magnitude system itself is a second argument for Hipparchus’

authorship of the first stellar catalogue. The creation of an accurate

magnitude system would require observing the relative brightness of stars

across the entire sky. It is a limitation of the human eye that only a few


245 Neugebauer (1975) 280 suggests that ‘a few main stars would suffice once theinvariance of all relative positions between fixed stars is established’. This case,argues that Hipparchus needed, and knew, the positions of only a few stars—thediscovery of the precession of the equinoxes did not require the basis of a stellarcatalogue.I feel that this argument is weak in two areas. First, as Neugebauer states, Hipparchuswould first need to determine that the ‘main stars’ do not change their relativeposition. To achieve this, the position of the ‘main stars’ would need to be measuredfrom at least two or three of their neighbouring stars over a period of time. Thus,this observation alone would result in the determination of the position of a farlarger number of stars than merely the ‘main stars’.My second objection to Neugebauer’s conclusion is his suggestion that only a fewstars are needed as reference stars. In theory, an astronomer would need only tworeference stars to measure the position of a planet, but, practical considerationsurge a knowledge and use of more than two. During the course of observation, theaccuracy of any measures can be increased by increasing the number of measures andaveraging the result (and removing any obviously incorrect measures). Also, due toweather effects (cloud, fog, haze etc.) a portion of the reference stars may not bevisible when needed. By having a larger number of stars to draw upon, the chance ofaccurately measuring the planet’s position is increased.

degrees of our field of sight is clearly distinguishable at any one moment.

degrees of our field of sight is clearly distinguishable at any one moment.

With this in mind, the procedure by which Hipparchus may have measured

the brightness of the stars, may have been to estimate the relative magnitude

of each star in each constellation (or in the case of the larger constellations,

a section of the constellation) and then compare the brightness of stars of

adjacent constellations. This procedure would be repeated until an ‘even’

measure of stellar magnitude existed over the entire sky. Thus a fair

percentage of the visible stars would have had to have been observed to

produce the magnitude system. If we assume that Hipparchus was as

methodical in the development of his magnitude system as he was with

his known work, then he would have accurately located the stars whose

magnitude he was measuring. The result of this procedure would not only

be a catalogue of stellar magnitude but also a catalogue of stellar positions.

Both the accurate measurement of planetary and Lunar movement and the

development of a magnitude system required a knowledge of the accurate

position of stars spread across a sizable area of the sky. This is the basis

for a positional stellar catalogue. It would be reasonable to assume that

Hipparchus would not stop at this point, with a major potential work only

partially complete, but would carry out whatever additional observations

were needed to complete the first stellar positional catalogue with a

magnitude system. As Neugebauer argues, however, there is no strong

evidence as to the nature of the coordinate system used by Hipparchus.246

He further argues that, while Hipparchus may have developed the magnitude

system, Ptolemy added to it by including divisions to the system above

and below full magnitude values.


246 Neugebauer (1975) 280 argues that Hipparchus’ catalogue did not use orthogonalcoordinates but merely a ‘latitude’ system based around the number of degrees a starwas distant from a celestial circle and an ecliptical system where a star’s positionwas identified in relation to the ecliptic. He suggests that the orthogonal coordinatesystem was the invention of Ptolemy.

It seems, though, that Hipparchus can be credited with the creation of the

magnitude system and a stellar catalogue of some description. How superior

Ptolemy’s catalogue was to Hipparchus’ and its degree of dependence,


are questions to which Manilius can provide no answers.

are questions to which Manilius can provide no answers.

3.6.5 Conclusion

Book Five of the Astronomica contains the earliest extant reference to a

stellar magnitude system. This evidence of the system’s existence prior to

the time of Ptolemy247 suggests that Hipparchus was its author. This

conclusion in turn suggests that Hipparchus also constructed a stellar

catalogue of some degree of sophistication. These conclusions are not an

indication that Manilius was directly familiar with the work of Hipparchus.

On the contrary, this usage (constellation magnitude and not stellar) suggests

an astrological intermediary between Hipparchus and Manilius.

___________________The Colour of the Star Sirius in Antiquity 152

247 The Almagest catalogue contains 154 stars (out of 1008) which are given amagnitude greater or lesser than a specific integer, e.g. 3+, i.e. slightly brighterthan 3rd magnitude. This development is likely to be Ptolemy’s contribution to themagnitude system.

Chapter Four: The Colour of the Star Sirius in

Antiquity

4.1 Introduction

The star Sirius is the brightest star in the Earth’s sky and for all of

recorded history it must have been so, but while its brightness has not

changed, its observed colour may have. In the modern era Sirius is blue-

white in colour, but in antiquity some authors referred to it as a red

star.248 Theories of stellar evolution tell us that Sirius in its current stage

of development is white, and should have been white for the last one to


248 The visual colour of a star is dependent on two attributes: its surface temperatureand its brightness. The first of these, the surface temperature, directly controls thestar’s colour. A ‘cool’ star is reddish in colour, a ‘hot’ star, whitish in colour(analogous to a piece of burning wood, which changes colour from red to white as itstemperature increases). The second factor is the star’s brightness. Human colourvision is effective only when an object is above a sufficient level of brightness. Forthe human eye to perceive a star’s colour, the star must have a high intrinsicbrightness. If a faint star were to be red in colour, humans would not detect itscolour, it would be perceived as white. Only a few stars are bright enough for humansto perceive their true colour, and Sirius is one of these. For a discussion of thehuman eye for astronomical purposes see the article by Jooste.Sirius is an A1 type star with a surface temperature of 10,000 degrees kelvin,approximately twice the surface brightness of the Earth’s Sun. This is sufficient togive it a colour of white (the ‘blue’ is an artifact of human vision).Dr. P. Bicknell (Monash University) has supplied me with the following informationconcerning Sirius’ colour. Patrick Moore (a British populariser of astronomy) askedEnglish viewers of his astronomy programs to tell him the colour they believedSirius to be. He received over 5,000 replies. Seventy-five per cent of the repliesstated that Sirius was white or blue, while the remaining 25 per cent gave a colourof red, orange, yellow, green or flashing in colour. This last clearly refers to Sirius’appearance when near the horizon and subject to scintillation. If we assume thatMoore’s viewers possess an above average knowledge of astronomy, then we find that25 per cent of astronomically aware people in the modern world believe that Sirius’true colour is that of its rising or setting. This suggests that it would not be impossiblefor ancient authors also to mistakenly believe that Sirius was red.

three million years, while before this period Sirius was a red star. Therefore,

three million years, while before this period Sirius was a red star. Therefore,

unless something is drastically wrong with current astronomical theory,


Sirius could not have been red a mere two thousand years ago.

Sirius could not have been red a mere two thousand years ago.

4.2 Modern Discussion

The question of the discrepancy between ancient comment and modern

observation has been discussed in a casual way over the last two hundred

years. The first modern reference to Sirius’ ancient colour was by the

Rev. Stukeley in 1760 and since then the matter has been discussed

periodically to the present day.249 To explain its apparent redness modern

astronomers have proposed a number of different mechanisms: changes

to human colour perception, visual impairment of observers and dust

clouds reddening Sirius’s light. With one exception none of these have

been offered with any great deal of plausibility.

The one and only proposed mechanism that does not stretch the realm of

credibility was outlined in a letter to Nature in 1986.250 Here the authors

suggest that a small explosion occurred on Sirius’ surface ejecting debris

into space. These ejecta would have filtered Sirius’ light, colouring it red.

While this is possible it has not been observed elsewhere, merely deduced

as a mechanism to explain the observations of antiquity. If, however,

such an explosion did occur on Sirius, it would have happened rapidly,

and over the space of a few months Sirius would have become brighter

and changed from a white to a red star. There is no suggestion of such a

dramatic change in any of the ancient sources. Also, the red appearance

of Sirius resulting from this event would exist for no more than two and a

half centuries, not the approximately one thousand year period suggested

by classical sources. Thus, while this mechanism is not impossible, there

is no observational support, nor does it agree with the purported records


249 Rev. Baker (1760).250 Frederick C. Bruhweiler, Yoji Kondo, Edward M. Sion (1986).

of a red Sirius.

of a red Sirius.

4.3 Ancient Sources

Sirius is part of the constellation Canis Major which shares the honour of

being one of the two hunting dogs of Orion the Hunter. Sirius itself has

received prominent mention in classical cultures. To the Egyptians, its

heliacal rising indicated the imminent Nile flood; but to the Greeks and

Romans its appearance heralded the heat of summer, and with it, many

associated ill events. This tradition has continued to the present day with

such expressions as ‘dog days’.

The belief in Sirius’ ill effects stems from three factors, the first being the

date of its heliacal rising in mid-July. When Sirius rises, the heat of the

northern summer is upon the Earth. Secondly, at its heliacal rising Sirius

appears as a bright red, ‘flashing’ object. It is this time that Sirius seems

to have been most observed.251 Lastly, there is the factor of Sirius’ intrinsic

brightness. It is not only the brightest star, but it is also very bright. To

the astrologically inclined these factors create both the astrological

prominence of Sirius and its ill-fated nature.

Five classical authors, Homer, Cicero, Horace, Seneca and Ptolemy, seem

to have identified Sirius as being red in colour, but, Sirius is also mentioned

by several writers who do not give a colour.252

I offer, as the first piece of evidence as to Sirius’ true, ancient colour, the

fact that only five authors suggests its redness, while the majority are


251 This is an important point. If Sirius was generally observed at its heliacal rising,this (red) appearance would have become part of its ‘popular’ image, and thus thequestion of Sirius’ colour is more easily answered.252 A partial list follows: Hesiod Works and Days 587–88, Aeschylus Agamemnon,967, Horace Satires I.7.25–6, Virgil Georgics II.353, Hyginus Fabulae 2.35.

silent on its colour. There are only five bright red stars in the sky, so the

silent on its colour. There are only five bright red stars in the sky, so the

‘normal’ colour of stars is white. If Sirius was white, then there would be

little need to describe its colour. If it was red, then this redness would be

mentioned far more frequently than in the few references listed here.

The Greeks and Romans were not the only peoples to watch the sky. The

various Mesopotamian civilisations and the Chinese empires recorded the

movements of the stars and planets for astrological purposes. Their

observations should be able to assist us with this question, but unfortunately

they do not; Mesopotamian and Chinese sources are inconclusive. Let us

therefore turn in more detail to the Classical authors who describe Sirius

as red in colour as red to see if we may interpret their claims in any other

way.253

4.3.1 Homer

Homer is the earliest author allegedly to label Sirius red. Since in three

passages in the Iliad he compares Sirius with bronze armour, his

comparisons have led several astronomical authors to conclude that Homer

considered Sirius to be the colour of bronze, i.e. reddish. Let us look at

these passages in question.

The first of these is found in Iliad, Book Five, lines 4–7. Diomedes is

given bronze armour by Athena from which a fire shone, like that of the

autumn star—Sirius.


253 Bonnet-Bidaud (1990), Tang, Tong B. (1986).

In line 7 Sirius is referred to as ‘washed by the Ocean’. This suggests that

Homer is describing Sirius at its moment of rising.254 As Sirius is subject

to atmospheric scintillation when it is rising or setting, its appearance at

this moment would be red. Thus Homer was comparing Sirius to bronze

armour during a moment when Sirius was perceptibly red.255

The second reference from the Iliad occurs in 11.61–66, where it is now

Hector who is compared to Sirius.

To begin the discussion, we should first ask if we can even be sure that

Sirius is referred to here, since the phrase ‘ ’, could also be

applied to a comet, but we shall assume for the sake of argument that

Homer is referring to Sirius.256 The passage tells us that Hector flashed

across the field of combat as this evil star flashes in the sky. Homer then

tells us that, like the lightning of Zeus, Hector flashes in his bronze

armour. There is only an imputed suggestion linking the colour of Sirius


254 Kirk (1990) 53 does not provide an indication as to Sirius’ colour. He doessuggest that ‘washing’ implies brightness without providing an indication as to theposition of the star.255 Rather than interpret this as a colour, it is possible that Homer was indicating thebelief that Diomedes’ armour was now the possessor of the ‘power’ (that of thebrightest star) of Sirius. If this is so, it renders invalid any conclusion that thepassage indicates Sirius’ colour.256 Kirk (1993) 226 takes the view that Sirius is referred to here.

to that of Homer’s bronze armour. There is no clear comparison, but no

to that of Homer’s bronze armour. There is no clear comparison, but no

other star is likely to be the one which is compared to him here.

The third and final Homeric reference to Sirius is found in Iliad 22.25–32.

Here, Achilles prepares to fight Hector, and to indicate how Priam viewed

the approaching hero, Achilles’ armour is described as shining in the

same fashion as the light of Sirius - an evil, fever bringing star with a

coppery colour ( ). The worth of this statement of colour should be

tempered by line 27 that refers to Sirius as the star of harvest-time, i.e. in

mid-July when Sirius experiences its helical rising.257 Thus, as with the

first Homeric reference, the third suggests that Sirius was popularly

perceived as a red star, rising with the Sun.258

Thus, none of the references to Sirius by Homer proves conclusively that

Sirius was red at all times. The first and third references by Homer seem

only to suggest the redness of Sirius at its rising, while the second gives

no hint as to Sirius’ colour.


257 Richardson (1993) vol vi 109 states that Homer is referring to Sirius’ helicalrising.258 Kirk (1993) 108-9 states that Achilles now has the nature of Sirius but does notcomment on the colour of the star.

4.3.2 Cicero

The next author whose works have been used as a basis for the claim that

Sirius was red is the Roman statesman Cicero. In his translation of Aratus’

Phaenomena Cicero clearly describes Sirius as deep bronze colour, rutilo

cum lumine claret feruidus Canis.259 However, he also mentions Sirius in

two of his later works without giving it a colour.260

The source of Cicero’s astronomical knowledge was Aratus, who discusses

Sirius in lines 326-36. Of interest is the context of the description, where

Sirius’ appearance is described at its heliacal rising (332ff.) This supports

the suggestion that Sirius’ ‘popular’ image was that of its heliacal rising.

Aratus himself makes no claim for a red Sirius either in the precise

reference to Sirius (330-1) or in the complete passage.

Two possible means of reconciling the inconsistency between Aratus and

Cicero present themselves. The first is that Sirius changed colour, from

white to red, between the third and first centuries. This hypothesis would

require positive verification by later authors, which does not exist. The

second, that Cicero made a slight error in translation, possibly influenced

by Aratus’ description of Sirius at its heliacal rising and by contemporary

tradition which perceived Sirius as red/evil.261 Perhaps it should be noted

in passing that Cicero tells us that he did translate Aratus when he was a

young man (admodum adulescentulus).262 Whatever the reason for this


259 Cic. Arat. 107–8. Cicero’s colour of rutilus does differ from the subsequent ‘redcolours’ of Horace, Seneca and Ptolemy. He seems to agree with Homer in givingSirius a ‘coppery’ colour. Here, possibly, Cicero is following his Homer.260 de Nat. Deorum 2.114.2 fervidus ille canis stellarum luce refulget and de Div.1.130, where there is a discussion of how the people of Ceos observed the heliacalrising once a year to determine the health of the year. There is no mention of colour.261 It has been suggested that Cicero was not attempting a ‘word for word’ translation,but that rather he was interpreting Aratus, Montanari 62.262 de Nat. Deorum 2.104, Ad. Att. 2.1.11

divergence between Aratus’ Phaenomena and its Latin translation, Cicero’s

divergence between Aratus’ Phaenomena and its Latin translation, Cicero’s

unsupported evidence cannot be taken as a reliable statement of Sirius’

colour.

4.3.3 Horace

We now turn to Horace, a prolific poet of the Augustan era. In c. 30 B.C.

he published his second Book of Satires, in which he mentions the star

Sirius and calls it red (Satires 2.5.39–40): ...seu rubra canicula findet /

infantis statuas. While this clearly states that Sirius is red, the reference

comes to us not as a deliberate attempt at describing the heavens but in

the middle of a satire on the legal process in which he is describing a

means to obtain a large inheritance. The allusion to Sirius may have been

no more than a minor illustrative indicator of social evil, using the popularly

red Sirius as a comparison. It also has been suggested that this line is not

pure Horace but a quote or parody of the poet Furius Bibaculus.263 There

is also the possibility that, as Sirius seems to be associated with the

change of seasons, this line in Horace may refer to its heliacal rising

during the winter months.264 The nature of the work itself makes questionable

the validity of Horace’s comment.265

4.3.4 Seneca

The next author who calls Sirius red is the Stoic statesman Seneca. In his

Quaestiones Naturales, Seneca refers to Sirius as a red star, speaking of

Caniculae rubor.266 If this is examined in isolation from the rest of Seneca’s

work, it would be strong evidence for a red Sirius, but in the same line


263 Rudd (1966) 120, cf. Fairclough 200-1, fn c.264 Astron. 1.397-9, Sirius is associated with winter and summer. The lines followingthe above suggest this.

Seneca describes the colour of two other astronomical objects that raise

Seneca describes the colour of two other astronomical objects that raise

the question of his overall reliability.

Following the description of Sirius, Seneca describes Mars as Martis

remissor. Here the redness of Mars is considered less than that of Sirius,

yet, Mars has a strong, red colour. If Sirius were redder than Mars, then

Sirius would be red indeed. A description of Jupiter follows that of Mars,

which is even more puzzling. Seneca states that Jupiter has no colour, its

colour being pure light, Iovis (rubor) nullus in lucem puram nitore perducto.

This last certainly raises a question as to the validity of Seneca’s testimony.

The planet Jupiter is white in colour, (with a slight red/orange tinge). If

Seneca is speaking from an astronomical perspective, then he has made at

least one possible error in assigning colour by stating that Jupiter is white.

If we assume that he is speaking from a Stoic viewpoint, then his assignment

of colours is based on the astrological significance of these three objects.


265 Dr Bicknell has suggested that the satirical nature of this reference providesinsufficient cause to dismiss its evidence. In defence of my suggestion that theobservational validity of Horace’s astronomical references cannot be taken at facevalue, I offer the following list of modern poets who have referred to Sirius as red:Martin, Martha E. The Friendly Stars, 1907 (referenced from Burnham 682)Sirius’ rising:—‘He comes richly dight in many colors...from tints of ruby and sapphireand emerald and amethyst’.Willis, Scholar of Thebet ben Khorat'Mild Sirius tinct with dewy violet'Tennyson, The Princess 5.262the fiery Sirius alters hueAnd bickers into red and emeraldThese three authors call Sirius red or multi-coloured, yet there is no question as tothe colour of Sirius in the modern world. These three use poetic licence to give thema more interesting and colourful star to describe. Scientific accuracy should not besought in poetry. I conclude that popular, non-astronomical works cannot be trusted,either in the ancient or modern world, to render astronomical observations accurately.266 NQ. I.1.7–8: ...sed acrior / sit Caniculae rubor, Martis remissor, Iovis nullus in /lucem puram nitore perducto267 Seneca refers to Sirius as ‘fire-like’. NQ. 7.1.5 ... si rarus et insolitae figuraeignis apparuit ...

Sirius is evil,267 therefore it is the reddest of the three; Mars is not evil,

Sirius is evil,267 therefore it is the reddest of the three; Mars is not evil,

but it is associated with the God of War and thus is red, although not as

red as Sirius; and Jupiter, being pure, has no colour and so it is white.

The possibility of an ‘astrological’ bias is raised also by three Senecan

references to allegedly ‘red comets’.268 These three passages are important

as comets do not have any colour. They are white, and no comet has ever

been red. It is clear that Seneca was describing comets in their astrological

sense as ‘bringers of evil and bad tidings’, and he was not providing an

astronomically accurate description. This being the case, it is highly possible

that Seneca’s description of Sirius as red equally reflects an astrological


268 NQ. 7.11.3: ita ait aut lucidiorem ese aut rubicundiorem et crines aut in interiorareductos aut in latera demissos. NQ. 7.15.1: Primo igneus ac rubicundus orbis fuitclarumque lumen emittens, quanto vinceret noctem. This comet is associated with thedeath of Demetrius Soter (151 B.C.) and the Achaean War. NQ. 7. 16.3: Comets ...Multi variique sunt, dispares magnitudine, dissimiles colore; aliis rubor est sineulla luce, aliis candor et purum liquidumque lumen. This last view of comets may bethat of Apollonius of Myndus and not of Seneca himself.

bias.

bias.

4.3.5 Claudius Ptolemy

We now turn to the work of Ptolemy, whose reputation rests on a summary

of Greek astronomical thought, written in the first half of the second

century A.D. His work, popularly known as the Almagest, covered every

aspect of ancient astronomy in thirteen Books.

One section of the Almagest is a stellar catalogue describing the location

of the constellations and brighter stars. In his stellar catalogue, Ptolemy

tells us that Sirius is red, .269 This, from the most important

astronomer in antiquity, would seem to settle the question of Sirius’ colour.

Stellar Catalogue, ‘The Dog’ (Almagest 8.1):

The belief, however, that Ptolemy was a great astronomer is only one

view of his contribution to astronomy and the possibility has emerged

that Ptolemy’s observations were fabrications, based upon earlier works,

and his calculations fraudulent. One of the major points discrediting Ptolemy

is his attribution of the colour red to Sirius, since it is clear that his claim

refers to an observation of the heliacal rising of Sirius, in conjunction

with an astrological consideration of Sirius’ as an evil (red) star.270

Thus Ptolemy’s reference to Sirius should be considered in the context of

his motivation for writing the Almagest. Ptolemy was an astrologer, and


269 There is a question as to the precise colour indicated by . According toLiddell and Scott (1940) 1884 this generally denotes yellow, except when it refersto stars when it does indicate the colour red - the sole example of this usage beingPtolemy. To clarify this matter it is clear that Ptolemy does used this word toindicate the colour red as he uses it to describe five stars that he correctly labels asred in his catalogue: Alpha Boo., Alpha Tau., Alpha Sco., Alpha Ori., Beta Gem.270 Newton (1977) 249.

he considered the Almagest an introductory work for his Tetrabiblos, a

he considered the Almagest an introductory work for his Tetrabiblos, a

work on astrology. While this does not invalidate his catalogue, it does

call into question his impartiality.271

In the larger context of the number and the importance of the questions

raised against his work, it is not possible to assume, without objections,

that his report of Sirius’ colour is valid.

4.3.6 Manilius

Manilius has the potential to cast significant light on the question of

Sirius’ colour, since in the Astronomica Manilius refers to the star on

three occasions. The first is a lengthy description of the star and its

astrological effects (1.396–411), the second and third references occur

much later in his work, where he describes the star in a strictly astrological

context (5.17, 5.207).

In an attempt to answer this question we must look at each statement in

the first reference in detail. Lines 1.396–400 refer to the ‘violence’ of the

star. This must clearly refer to Sirius and not to the constellation; as noted

above, Canis Major is not a prominent constellation in itself. Lines 1.401–6

also clearly refer to Sirius, because they discuss the astrological effect of

Sirius’ heliacal rising on the Earth. Line 1.407 refers to the ‘fire of Sirius’.

Line 1.408 states that Sirius is as bright as the Sun but that its light comes


271 Dr P. Bicknell has made the observation that Ptolemy’s stellar catalogue wastranslated by Arab astronomers during the period of the European Middle Ages, andthat Sirius continued to be listed as red in these translations. It is assumed thatSirius’ colour was white, and known to be white, in this later period. If so, thequestion arises as to why Arab astronomers did not correct the catalogue and listSirius as a white star? As this error went uncorrected it does suggest that an errorof this type could be overlooked or accepted, or that the translaters preferred torepeat what the original document said, rather than rewrite it.

from a great distance. Skipping over 1.409 (the line that refers to it as

from a great distance. Skipping over 1.409 (the line that refers to it as

caeruleus) we come to the concluding lines of this passage, 1.410–1.

Here Manilius refers to Sirius as the brightest star in the heavens and

once again describes its appearance at its rising and setting.272

In line 1.409, Manilius refers to Sirius (canicula) as having frigida lumina

with a caeruleus vultu.273 This description matches the visual impression

of Sirius as it is today (cold brightness in a blue face). In a dark, clear sky

Sirius’ brightness does appear cold and penetrating. The sea-blue colour

is equally accurate. While Sirius’ predominant colour is white, after a few

moments observation, definite tinges of blue become apparent.

As a counterpoint to this, and an illustration of the possibility of colour

ambiguity, in the same passage Manilius refers to ... micantis ignis ad os,

(1.407–8)—’quivering ... fire ... in its face’. Here, Manilius is referring to

the ‘burning’ brightness of Sirius at its heliacal rising viewed from Mt.

Taurus (1.402). It is possible however, were it not for caeruleo, to interpret

this as a suggestion that Sirius is red or ‘burning’. As mentioned previously,

other ancient authors use such ambiguous descriptions of Sirius. Here it

can be seen that such apparent ambiguity in an ancient author is not in

itself sufficient to create a convincing argument for a classical red Sirius.274


272 Manilius also refers to Sirius at its heliacal rising at 5.218ff.273 1.396–411: subsequitur rapido contenta Canicula cursu, / qua nullum terrisviolentius advenit astrum / nec gravius cedit. nunc horrida frigore surgit, / nuncvacuum soli fulgentem deserit orbem: / sic in utrumque movet mundum et contrariareddit. / hanc qui surgentem, primo cum redditur ortu, / montis ab excelso speculanturvertice Tauri, / eventus frugum varios et tempora discunt, / quaeque valetudo veniat,concordia quanta. / bella facit pacemque refert, varieque revertens / sic movet, utvidit, mundum vultuque gubernat. / magna fides hoc posse color cursusque micantis /ignis ad os. vix sole minor, nisi quod procul haerens / frigida caeruleo contorquetlumina vultu. / cetera vincuntur specie, nec clarius astrum / tingitur oceano caelumquerevisit ab undis.

With the possible exception of 1.409, this passage consistently refers to

With the possible exception of 1.409, this passage consistently refers to

Sirius. The question of 1.409 is difficult to answer. Dr Bicknell has stated

that it does not refer to the star but to the night sky within the constellation.275

Two points can be made in response to this. Even though Manilius uses

caerulis in Book One to refer to the colour of the night sky there is no

reason why he cannot use the same term for a different purpose. The

second point is that it does seem unlikely that Manilius begins this passage

with a description of Sirius, then for one line refers to the constellation

before switching back to Sirius and his earlier discussion.It is my conclusion

that this passage does describe Sirius’ colour as blue-white.

There are two later references that discuss the nature of Sirius in terms

that could be interpreted incorrectly. In 5.17 Manilius refers to Sirius as

et Canis in totum portans incendia mundum. Later, in 5.207, he gives a

four line description of the astrologically destructive effects of Sirius

(Canicula). Here he uses terms such as candens, flammas, rabit, radio

and cinerus, all terms that could be interpreted as indicating a red Sirius.

These indicate that a simple statement of Sirius’ blazing, burning nature

and its resultant ill effects, are not sufficient unto themselves to convincingly

argue for a red Sirius.

In summary it can be seen that the Astronomica encompasses much of the


274 An alternative translation and explanation for these lines comes from Dr Bicknellof Monash University. He has suggested that 1.409 refers not to Sirius itself, but tothe constellation Canis Major. His argument is that Sirius is the tongue of the Dog andthat the Dog hurls ‘cold light from its dark-blue constellation’. Bicknell suggeststhat caeruleo ...vultu is the ablative of origin, linking the dark-blue colour with the‘face’ of the constellation Canis Major, the colour of the night sky, not that of Sirius.Manilius does use ‘caerulis’ to refer to the night sky in Book One. Saccheti (1993)105 suggests that Manilius uses ‘caerulis’ in contrast to the bright, white stars. Thequestion is whether he was using the same meaning in 1.409.275 In 1.647 Manilius refers to the Sun’s light as cold et gelidum extremo lumensentimus ab igni. This is a similar sentiment to which is expressed in 1.409 andsuggests that Manilius can refer to a bright (and white) object in such terms.

debate as to Sirius’ colour and assists in reaching a conclusion as to its

debate as to Sirius’ colour and assists in reaching a conclusion as to its

colour. It contains a line which suggests that Sirius was white in the first

century A.D. It also refers to Sirius in terms that could be interpreted as

suggesting that it was red. Manilius’ work contained a preponderance of

astrological material. It would have suited him if Sirius was red, thus

agreeing with its astrological effect. If an unambiguous statement that

Sirius’ true colour was red was to be made it would have been made here,

but it is not. This combined with Manilius’ (likely) statement that Sirius

is blue-white argues very strongly against a red Sirius.

4.4 Conclusion

The evidence that suggests that Sirius was red in antiquity is capable of

varying interpretation. Homer’s evidence is questionable and can be equally

interpreted as an argument for a ‘white’ Sirius. Cicero’s translation of

Aratus contradicts the original. Horace’s satires are a poor astronomical

source. Seneca clearly reflects an astrological orientation. Ptolemy,

notwithstanding his reputation as an astronomer, was also an astrologer.

Weighed against these sources are the far larger number of authors who

describe Sirius’ nature as ‘scorching’ and ‘evil’ but do not assign a colour,

and the testimony of Manilius who states that Sirius was white.

On the balance of probabilities, there is insufficient evidence from Greek

or Roman sources to prove that Sirius was red in antiquity.

___________________The Astrology of the Astronomica 168

Chapter Five: The Astrology of the Astronomica

5.1 Introduction

For Manilius, astrology is the means by which human beings may learn

their fate. By observing the heavens and using the appropriate astrological

skills imparted, however imperfectly, in Books Two, Three, Four and

Five, a student of Manilius may uncover what fate has in store. While

astrological technique consumes the bulk of the Astronomica, the theoretical

basis for astrology occupies only a few lines. It is these lines, involving

Manilius’ justification and explanation for astrology, that will be examined

in this section.

While Manilius followed a Stoic interpretation of astrology, there is also

evident an indication of what may be called a ‘scientific’ approach.

Astrology was justified not only by Stoicism but also by empirical

evidence.276 It is also clear that Manilius viewed astrology as the greatest

form of divination, superior to all others. It was also more than merely a

way of foretelling the future, since it was a means by which human

beings could aspire to learn the mind of God and a step in the process of

achieving their own form of divinity. It is also clear that Manilius did not

view astrological procedures in themselves as being of prime importance.

5.2 A Philosophical Basis for Astrology


276 Sikes (1923) 174 suggests that Posidonius was responsible for the final unificationof Stoicism and astrology, since Posidonius was a researcher who travelled extensivelyand wrote on a wide variety of topics in a ‘scientific’ fashion.

There are four major descriptions of the philosophical basis for astrology

There are four major descriptions of the philosophical basis for astrology

in the Astronomica, found within the larger discussion of the nature of

Manilius’ Stoicism. Each will be individually examined to determine the

common themes and their specific rationale for astrology.

The first description is found in Book One, lines 25–117, and constitute

Manilius’ first ‘history’ of humanity, in which he outlines human

development. The specific reference to astrology occurs in 1.107–12, a

passage which gives a brief overview and rationale for astrology, asserting

its existence and ascribing the determination of life’s rules to the universe

(the Stoic God—numen mundi, 1.111). Here the poet grants to the

constellations an expression of fate and human life, stating that fate follows

fixed rules (certa sub sorte) which are displayed by the stars (1.112).

The next major discussion is found in the opening lines of Book Two

(2.80ff.), where Manilius explains this linkage between the stars and the

Earth. The linkage is based on the harmony and interrelationship of the

different components of the universe and on the centralised control exercised

by God, described earlier in lines 2.60–81. By virtue of this harmony and

control, what appears in the heavens influences what occurs on the Earth,

as we see in 2.82–3.

hic igitur deus et ratio, quae cuncta gubernat,

ducit ab aetheriis terrena animalia signis,

Manilius then answers what may have been a question in the minds of

many of his readers: ‘How can something as far away as the stars affect

my life on Earth?’.277 He points out that it is God’s plan that the stars may


277 It should be mentioned that Manilius had placed the stars at the farthest possiblepoint from the Earth in his account of Stoic cosmology (1.150ff.)

effect life on the Earth. Their distance is irrelevant (2.84–5).

effect life on the Earth. Their distance is irrelevant (2.84–5).

quae, quamquam longo, cogit, summota recessu,

sentiri tamen, ...

Finally, Manilius specifically states that the stars furnish knowledge of

lives, destiny and character (2.85–6).

...ut vitas ac fata ministrent

gentibus ac proprios per singula corpora mores.

These lines suggest that God totally controls the lives of nations and of

individuals.278 The lines can be read as an introduction to the detailed

astrological information found in the remaining four Books of the

Astronomica. This introduction serves as a concise explanation for

astrology, stating that astrology exists as an intrinsic component of the

Stoic universe, and affecting everyone in every way.

These themes are repeated in 3.43ff., where Manilius recounts a second

history of the creation of the universe.279 He repeats his argument that the

various components of the universe are controlled by God (natura, 3.47)

and are in harmony (concordia, 3.54). We see this in 3.50-1: ...diversaque

membra / ordinibus certis sociaret corpus in unum, and in 3.54–5: ut tot

pugnantis regeret concordia causas / staretque alterno religatus foedere

mundus ...

The work argues again for the interrelationship of everything in the universe:

the stars, the planets, the Earth and human beings. Manilius states


278 cf. Colish (1985) vol. 1, 32ff., Sikes (1923) 173.279 The first account of the creation of the universe occurs in 1.149–72.

specifically that human beings are subject to this interrelationship. He

specifically that human beings are subject to this interrelationship. He

does this in two parts. First, he states that nothing should exist outside

this scheme, exceptum a summa nequid ratione maneret (3.56); secondly,

that, as human beings are born of the heavens, they should in turn be

controlled by the heavens, et quod erat mundi mundo regeretur ab ipso

(3.57). This leads directly to the next line, that ‘nature’ made human

destiny dependent upon the stars: fata quoque et vitas hominum suspendit

ab astris (3.58).

These lines repeat the argument of the first two passages,280 that the

universe was created and is controlled by God who wishes human beings

to know their fate. To this end, God makes human fate visible to us

through the changing appearance of the heavens—the rationale for

astrology. This is restated in 3.59–60.

quae summas operum partes, quae lucis honorem,

quae famam assererent, quae numquam fessa volarent.

In this passage Manilius has skilfully and concisely woven each facet of

the Stoic universe into an irrevocable conclusion that astrology is an

intrinsic part of the universe. He explains the history of the universe from

its inception through to this conclusion (3.43–66) which is in agreement

with what we know of the Stoic attitude to divination,281 which is similar

in intent to Manilius’ conception. Their major difference lies in the absence


280 This description of astrology, given in lines 3.43ff., provides another importantpiece of information. In lines 3.61–4, Manilius explains that natura gave to specialstars (the zodiac) the controlling influence over fate. This is significant as Manilius’astrology does revolve around the zodiac (per mediam, mundi praecordia, partem,3.61) with the planets having a far smaller role.281 Diog. Laert. 7.149 (using Zeno, Chrysippus, Posidonius, and Boethius) describesthe Stoic rationale for divination as the result of a chain of causation: God to fate todivination.

of astrology. Diogenes refers to divination in general: Manilius specifies

of astrology. Diogenes refers to divination in general: Manilius specifies

the art of astrology.282 A different rationale for astrology can be found in

Cicero, who lists the arguments put forward by the Stoics to demonstrate

that the gods created the signs for human understanding (de Div. 1.82–3).

This suggests that astrology was not fully merged into Stoicism until a

later period, possibly the Roman period (1st century B.C. cf. thesis section

2.1.5) of Stoicism.

The final account of astrology, in the conclusion of Book Four, takes a

different emphasis in its argument for astrological truth. Manilius does

not discuss the details of how astrology works but assumes that the reader

has already absorbed this information. Now he tackles the ‘why’ of

struggling to learn astrology, asking the rhetorical question, ‘Can human

beings learn the secrets of nature?’ Lines 4.876–83 form an answer to this

question. Human beings may learn these secrets by gaining an understanding

of the heavens (mundi ...census, 4.878).283 This is the essence of astrology,

that it is the means to learn of the Stoic universe. The concluding discussion

is a blanket statement which argues the benefits of the arduous task of

mastering astrology—knowledge of one’s fate and spiritual divinity.


282 Diog. Laert. 7.4 records how Zeno wrote a work entitled . The exactmeaning of the title is debatable but it may refer to ‘a sign from heaven’, or an omen.It is possible that Zeno recognised the existence of astrology as part of Stoicism, butthis work is only one of nineteen of Zeno’s cited by Diogenes Laertius. If Zenobelieved in astrology he did so without the single-minded emphasis found in theAstronomica. To add to the difficulty of determining the nature of Zeno’s work we cancompare it to Philodemus work of the same title. This, however, was concerned withEpicurean ‘methods of inference’ and not divination, Wigodsky (1995) 65. Philodemusbased his upon Zeno of Sidon’s teachings.283 Goold translates ‘census’ as ‘treasures’. This is a free but appropriate translation.Manilius is clearly attempting to prove the great benefits that a knowledge of Stoicastrology can bestow.

5.3 Empirical Arguments for Astrology284

5.3 Empirical Arguments for Astrology284

There are two other explanations for astrology found in the text. One is of

an ‘eastern’ origin, while the other has an ‘scientific’ basis. Both depart

from the general tone of the Astronomica. These two rationales for astrology

will be examined here, as well as the means by which Manilius interprets

them to support his dominant philosophical view of astrology.

The traditional argument for astrology is found in Book One, 40–65.

Manilius states that astrology was developed by long and painstaking

research by Egyptian and Babylonian priests. The adepts uncovered the

secrets of astrology by correlating an individual’s birth-time with the

subsequent events of life. This notion argues for an empirical basis to

astrology. This stated origin must be compared with Manilius’ primary

argument. Stoicism originated only three centuries before Manilius.

Between the time of Zeno and Manilius, we may assume that Stoics

worked to incorporate astrology into their fate-driven creed (thesis section

2.1.5). Lines 1.46–65 suggest that, even after this lapse of time, a purely

Stoic justification for astrology did not exist. The ‘ancient’ mysticism of

the east needed to be invoked to bolster the Stoic-astrological doctrine.

By including 1.46–65 in his introduction, Manilius recognises this past.

The scientific argument for astrology can be found in 2.82ff., where

Manilius provides a two-part explanation of astrology: the first, that

astrology is derived from the Stoic God; the second, beginning at line

2.87, nec nimis est quaerenda fides. He explains that the evidence he is

about to give is the proof that God controls fate and astrology. The

evidence includes several examples of a causal link between heaven and

Earth: the effects of the heavens on agriculture, the tides, sea life and


284 There is also a discussion of the use of historical example as a scientific basis forastrology in the thesis section on fate (2.4).

ranching. All of these examples are readily discernible to the ‘untrained’

ranching. All of these examples are readily discernible to the ‘untrained’

eye.285 Manilius apparently feels the need to support his theoretical Stoic

argument for astrology with readily observable evidence.

This argument is in accord with the defence of Stoic astrology preserved

by Cicero (de Div. 1.34), that there are two forms of divination: the first

relying on observation and conjecture, the second on ‘dreaming’. The

Astronomica clearly favours the former, and Cicero provides an example

of this with the statement that a man born under the star Sirius will not

die at sea (de Fat. 12–15). The validity of this prediction can only be

ascertained by observing the lives of men born under the influence of

Sirius and discovering if any, do in fact, die at sea. This method is

repeated by Cicero in de Div. 1.118 where he lists incorrect predictions.

To this school of divination, knowing the future requires study, skill and

a firm empirical basis.

A scientific approach (though not to astrology) is further documented in

Book One. As part of his introduction to Stoic cosmology, Manilius first

discusses six non-Stoic cosmological theories (1.122–44). By setting out

these theories, he was perhaps suggesting to his readers that he had examined

them and found them wanting, thus producing, in the mind of the reader,

the conclusion that all of the non-Stoic theories had been discussed, debated

and proven incorrect. The reader was being asked to believe that the Stoic

cosmological theory had passed these tests and was correct. Manilius was

suggesting that Stoicism was the only valid result of centuries of research

by the learned minds of the classical world.


285 There are a number of easily observable celestial phenomena that clearly correlatewith Earthly events. These include, for example: the tides and the moon; the appearanceof the Moon, Sun and some stars—such as the seven sisters—as guides to subsequentweather patterns. These phenomena existed in popular lore.

By calling upon the cognizance of eastern mysticism and of the scientific

By calling upon the cognizance of eastern mysticism and of the scientific

heritage of the Hellenistic period that were present in Roman society,

Manilius attempted to counter every challenge and fulfil every expectation

in the mind of his readers. To those who followed astrology he acknowledged

their beliefs and added to it a more ‘reputable’ Stoic justification. For

those who appreciated Greek science Book One subsumed astronomy

into astrology.

These examples of a ‘scientific’ basis for astrology and the Astronomica

form no more than a minor alternative to the main Stoic approach, yet

they reflect the diverse range of thought, sources and attention to detail in

the Astronomica. Manilius’ main argument for astrology was the Stoic


creed, yet he also justified it by logic and empirical evidence.

creed, yet he also justified it by logic and empirical evidence.

5.4 The Worth of Manilius’ Astrological Procedures

Books Two, Three, Four and Five of the Astronomica include approximately

four major different procedures for casting a prediction. These procedures

overlap and contradict each other, are incomplete and some are mutually

exclusive. They are also all provided with insufficient detail to be put into

practice. This being the case, why did Manilius bother to include this

material only to misuse it? The answer to this question demonstrates

Manilius’ view of astrology. To him the heavens were merely the visible

face of the deity that created and controlled the universe. The details of

astronomical and astrological technique were, if anything, almost a

distraction from the underlying truth of the universe. A Stoic did need to

know these details, but they were only the starting-point to the search for

God.286 The fact that Manilius’ astrological procedures did not make sense

in a ‘rational’ sense was to him irrelevant because they all provided a

path to Stoic enlightenment. To learn and to know each procedure in full

would be to make the mistake, from Manilius’ perspective, of confusing

the image of God with the reality.287

__________________The Horoscope Formulae of Book Three 177

286 An example of this thinking may be found in Plato’s Republic 529–530c, wherethe student is referred to astronomy but warned against confusing it with the truthbehind it.287 An alternative possibility is that Manilius included only partially completeprocedures as he believed that this information should only be distributed by himselfand not released to the general public. Maranini (1994) 41-2 discusses the possibilitythat Manilius did not write all of what he knew as he intended the work for a selectaudience. While this option cannot be simply dismissed, to grant it fully would be tolessen the importance of Stoicism in relation to astrology. Possibly Manilius didknow more astrology than he included in the Astronomica but he excluded it becauseof its lesser importance, not because he wished to hide secrets. Also because hewished to avoid the imperial entanglements of providing procedures that could casthoroscopes.

Chapter Six: An Astronomical Examination of the

‘Horoscope’ Formulae of Book Three

6.1 Introduction

In the astrological Books of the Astronomica (Books Two to Five), Manilius

describes a range of different astrological procedures. In order to discern

Manilius’ attitude to the ‘mechanics’ of astrological prediction I shall

carry out a detailed analysis of one of these procedures. My choice for

this examination is the principal procedure of Book Three which is based

upon the astrological concept of ‘athla’ (3.162–3) as the controllers of

fate and destiny.288 This decision is based upon the significant size and

detail of their description as well as the potential to elicit astronomical

information.289 The entire account of the athla and the beliefs surrounding

them is given in 3.43–509.290 The astronomical relevance of the athla lies

in their concomitant formulae used to calculate the horoscope (that part of

the zodiac rising on the horizon at the moment of the subject’s nativity).

This section will examine these formulae with a view to determining their

astronomical worth and origin.291


288 In this passage Manilius makes a rare reference to the importance of the planets,stating that they influence the powers of the athla, but he does not provide details ofthe nature of this influence.289 Abry (1993) 195 states that Book Three, due to the presence of the athla, is themost ‘scientific’ Book of the Astronomica. I feel that this distinction belongs to BookOne as it describes, however poorly, the basics of spherical astronomy rather than agarbled account of one astrological theory.290 At a total of 467 lines this is the longest single account of an astrological procedurein the Astronomica.291 After examining the athla passages it is possible to venture a conjecture as totheir origin. The athla are clearly separate from the zodiac, in that they are independentfrom the signs, yet they share the zodiacal band and are divided into twelve sections.This suggests that the athla developed as an attribute of the zodiac and then evolvedinto a distinct astrological belief while retaining their initial attributes.

Before examining the athla in detail it is first necessary to understand the

encompassing astrological system. In Manilius’ schema, there are twelve

athla, each 30 degrees in length, arranged in a fixed order, and following

each other around the path of the zodiac, so that different athla are present,

in each sign, at different times.292 Each athlum controls a different aspect

of life and fate (e.g. health, marriage etc.). The details of the nature and

powers of individual athla are found in lines 3.69–159. To use the athla

the astrologer must first determine where its ever-changing starting point

is at the moment of the subject’s birth. The astrological procedure that

calculates this is described in 3.180–202, which provide two separate but

similar formulae, for both a day and by night. Both are based on the

position of the Sun, the Moon and the horoscope. For a birth by day (and

Manilius devotes six lines to informing his reader how to tell day from

night, 3.180–85), the astrologer must first determine the separation in

degrees between the Sun and Moon measured in an easterly direction

along the zodiac.293 Then that distance is measured easterly, along the

zodiac, from the horoscope. This final point is the first athlum, the ‘Lot of

Fortune’ (fortunae sors prima data est, 3.96) and the starting point of the

athla. The formula for a night-birth also begins with the determination of

the separation of the Sun and Moon, but in this case the separation of the

Moon from the Sun is also measured easterly along the zodiac. After this

has been found, once again starting from the horoscope, the astrologer

measures this distance east along the zodiac. The final point is now the

‘Lot of Fortune’.294


292 For ease of description, the twelve zodiacal constellations will be referred to as‘signs’.293 It should be stated that Manilius does not specify a direction of movement along thezodiac in his description of this procedure. Goold, in his two examples of the process,assumes that this direction is always easterly (Goold (1977) lxv–lxviii.) This is areasonable conclusion that I have used in my summary of the process.

The major difficulty facing any of Manilius’ disciples is the faulty nature

of his explanation of this procedure. This system requires three reference

points, all occurring at the moment of birth: the Sun, the Moon, and the

horoscope. The simplest way of obtaining these three positions would be

to resort to an almanac or celestial globe, yet this is not the advice given.295

In fact, Manilius explains to his patient reader how to find only one of

these positions, that of the horoscope, and uses a needlessly complex,

rambling and confused series of formulae to do so (3.218–509). The

determination of the position of the Sun and Moon is ignored in the text,

yet, without these, the ‘Lot of Fortune’ cannot be calculated. Manilius’

omission of a discussion of these points suggests that he was not concerned

with correct procedure, nor with teaching the reader the means to cast an

accurate prediction.

To summarise this discussion, we can see that Manilius provides a lengthy

account of a complex procedure whose apparent goal is the use of the

astrological concept of the athla. The bulk of this involves a series of

formulae used to derive the location of the horoscope. The casual reader,

or even interested student, would find the instructions both needlessly

complex and incomplete. In the text there is no systematic presentation

nor use of examples, nor a clear and concise exposition of the formulae.


294 These two formulae are difficult for a non-astrologer to reconcile. A difference ofonly a few minutes can give a child either a day or a night birth, which can shift the‘Lot of Fortune’ a great distance, depending on the initial position of the Sun andMoon.295 The existence of almanacs and charts of sufficient complexity to determine thisinformation were in existence at least from the time of Hipparchus in the mid secondcentury B.C., e.g. Jones (1995) 255-8. Goold (1977) lxviii suggests that Maniliusused his ephemerides for the location of the Sun. This is a reasonable statement, butthe question then arises; why did Manilius not simply use an almanac for the entireprocedure and not merely part of it? The answer lies in Manilius’ aims. He was notan astronomer, he had a mystical belief in the stars. The details were irrelevant tohim.

In addition to these difficulties Manilius has merged different methods

In addition to these difficulties Manilius has merged different methods

for determining the horoscope into his presentation, with a mixture of

irrelevance and duplication. Manilius clearly gave these formulae as ‘rules

of thumb’. There is no explanation as to how they work or how they were

derived. Lastly, the formulae themselves could be better understood if

there were more explanatory material. It is true that there is a smattering

of this in the formulae themselves and in the sphaera of Book One, but in

insufficient detail to be truly helpful. In sum, Manilius’ athla astrology is

an amalgam of incomplete procedures and mediocre presentation.

6.2 Summary of the Horoscope Formulae

Manilius begins his account of the horoscope with a formula that he

states is in common use, but this he speedily criticises and dismisses. We

are then introduced to the preferred formula, in three parts. The first part

describes its usage, but only for one band of latitude. The second explains

the inadequacy of this limitation. In the third he proceeds to describe,

with examples, an improved version of the formula that is effective for

any latitude. Manilius could usefully have stopped here, but he diverts his

attention from horoscope formulae to describe in equal detail a formula to

calculate the change in the length of the day over the course of the year.

This is of only marginal relevance to the text. He then concludes with a

more detailed version of his first (and incorrect) formula. As an aid to

understanding the following discussion, I have summarised the formulae

below.

1. 3.218–46

This formula is based on the belief that each sign takes two hours to rise.


By ‘counting back’ the number of hours the Sun is from the horizon, and

By ‘counting back’ the number of hours the Sun is from the horizon, and

then converting these hours to signs, the observer may find the birth sign.

Manilius implies that this method is in common use (3.218). Manilius

(correctly) explains why this formula is inaccurate-the ‘common’ hour

varies and the rise time of each sign is not two hours but varies according

to the position of the sign in the zodiac (its distance from the celestial

equator) and the latitude of the observation.

2. 3.247–74

For the observer to be able to rectify the errors of the first formula, he

must procure hours of equal length to produce accurate results. Manilius

describes how the length of day and night changes over the course of the

year, and he uses Egypt and the latitude of Rhodes as examples.

3. 3.275–300

Manilius now describes the first version of his principal formula. This

merely tells the reader how to determine the rise-durations and set-durations

of the signs,296 for one latitude, that of 35 degrees north. This formula is

based upon an initial rise-duration for Aries (given in hours and fractions

of an hour as well as in half degree units—stades) which is then used as a

basis for calculating the rise-duration of the other signs.

4. 3.301–84

This passage explains the deficiency of the preceding formula, in that it

is effective for only one latitude, rendering it useless for general use.

Manilius explains (again) how day and night vary in length over the

course of the year and that the rise-and set-duration of the signs varies


296 The definition of ‘rise’ is the period between the rise of the first point and lastpoint of the sign above the horizon. This is termed ‘rise-duration’ rather than ‘risetime’ to prevent any possible confusion between the amount of time a sign takes torise fully and the moment in time it begins to rise.

with latitude.

with latitude.

5. 3.385–442

Manilius now provides a new procedure effective for all latitudes. He

does this in two separate formulae, the first of which describes the rise-

duration of the signs in time (hours and fractions of hours), while the

second describes the same, but in stades. These formulae duplicate each

other, except for their unit of measurement, and they are independent of

the formulae of 1–4 above. Manilius takes credit for these two formulae.

6. 3.443–82

Manilius now provides a formula that calculates the change in the length

of day and night over the course of the year, although this is not necessary

for the calculation of the horoscope.

7. 3.483–509

This final formula is a repeat of the first. It describes the rise-duration of

each sign as 30 degrees, equalling 2 hours, the same indicator as in

3.218–46. This latter version is more complex but has the same principle

and flaws as the first.

The remainder of this section is a detailed examination of all of the

horoscope formulae.

6.3 The ‘Two hour’ Rise Formula: 3.218–46 (No. 1)

This is the first and simplest of the formulae given by Manilius. It is

based on the belief that each sign takes precisely two hours to rise, but

this assumption is incorrect, although not drastically so. As a general


guide, a two hour rise-duration (and set-duration) for each sign is reasonably

guide, a two hour rise-duration (and set-duration) for each sign is reasonably

accurate, and from the latitude of Rome, the variation would be less than

plus/minus 45 minutes. In his discussion, Manilius makes no attempt to

explain how the formula can be used.

After describing this method briefly (3.218–24), however, Manilius explains

why it is incorrect (2.225–46) and he also implies that it is in common

use 3.218 (Nec me vulgatae rationis praeterit ordo). This suggests the

reason for Manilius’ inclusion of this formula, that he presented it to be

criticised, debunked and then used to demonstrate the worth of his preferred

formula. In this way he differentiated himself from the common herd of

‘street corner’ astrologers, who no doubt plied the streets of Rome, catering

to the masses and occasionally incurring the Imperial wrath. As can be

seen, the poet devotes greater length to criticising this system than he

does to explaining it.

The criticisms that Manilius levels against this method are appropriate

and indicate his sound grasp of astronomical knowledge. He first points

out that the path of the zodiac lies at an oblique angle to both the horizon

and to the celestial equator (3.225–8).297 which causes each sign to rise at

a different oblique angle to the horizon with a correspondingly different

rise-duration. Those signs found closer to the celestial equator rise almost

vertically and quickly, while those lying further north or south of the

celestial equator rise at a lesser angle to the horizon and thus take longer

to rise. Manilius then points out another source of error in the first formula,

that it was ‘common’ practice, in antiquity, to divide the night and day

into twelve hours over the course of the entire year (3.229–37). This

resulted in a different length of hour between successive days and even


297 For a discussion of the obliquity of the ecliptic (zodiac), see Appendix A.

between the hours of the same day and night.298 Thus the street-corner

between the hours of the same day and night.298 Thus the street-corner

astrologer would ‘count back’ from the Sun a different length of the

zodiac at different times of the year, rendering measurement in hours no

more than an approximation. Manilius suggests that this was a commonly

accepted measure but was inadequate for the exacting task of serious

astrology, quem numerum debet ratio sed non capit usus 3.246. These

problems are discussed at greater length and answered in 3.247–74 as an

introduction to the second horoscope formula.

The first formula is simple in design but does possess a number of flaws.

Manilius is correct in his summary of these problems, but is possibly too

severe. With care, and a little intuition on the part of the astrologer, the

formula could be used to produce results of reasonable accuracy. There

are twelve athla, each taking 30 degrees of the zodiac. The horoscope can

fall anywhere within a single athlum and still provide the same result.

Thus a high degree of accuracy in the calculation of the horoscope is not

necessary, and the accuracy achievable by this formula would not always

give a correct answer but would do so perhaps 75 per cent (or more) of

the time, depending on the skill of the astrologer. Due to its simplicity

and reasonable rate of accuracy, the assertion that this procedure was in

common use is probably correct.299

6.4 Introduction to the Second Formula: 3.247–74 (No. 2)


298 For example, in winter, the hours of night are longer, while in summer thereverse is true. ‘Variable’ hours render accurate recording of astronomical eventsimpossible.299 Manilius is at pains to criticise this formula. This diligence, in search of thetruth, however, could be applied to his own astrological writings which have gapingholes in content and logic. This raises the question as to the reason for his criticism.It seems that he was not criticising the astrological procedure, so much as the‘common (non-Stoic) astrologers’ who used it.

After demolishing the first formula, Manilius launches into an introduction

After demolishing the first formula, Manilius launches into an introduction

to the second. This introduction provides a necessary item of background

information and adds detail to the criticism of the first formula. The

relevant item is the importance of uniform hours, which can be determined

only at the time of the equinoxes. The variation in the length of day at the

Nile delta is used as an example of how ‘variable’ hours are unreliable.

This leads directly into 3.275–300, where Manilius describes his second

formula, which is a more sophisticated and accurate method of determining

the rise-duration of the signs.

Manilius begins by stating that a fixed length hour must be used for all

calculations (3.247), in contrast to the ‘variable’ length hour used in the

first formula. A fixed length hour is achieved by calculating a ‘standard

hour’ on the day of the equinoxes when day and night are of equal

length—when the Sun enters Libra and Aries. This will produce an hour

equal to 1/24th of the total day. It would be correct to stop at this point

and move on to the description of the second formula but Manilius chooses

to add greater detail to this introduction by providing a guide to the

changing length of day and night over the course of the year (3.256–74).

The guide begins with a description of the heavens at the winter solstice,

when the Sun is in ‘chill’ Capricorn, when the day is 9.5 hours and the

night 14.5 fixed hours in length. The change in this ratio over the next six

month period is illustrated, when the days grow longer, the nights shorter,

and the equinox is passed and then the summer solstice of Cancer is

reached. Here the ratio of day to night is the reverse of the winter, which

Manilius states is found at the Nile mouth (3.271ff.).

Two points emerge from this passage. In 3.257, Manilius states that the


winter solstice occurs when the Sun is in the eighth degree of Capricorn.

winter solstice occurs when the Sun is in the eighth degree of Capricorn.

In all other such references in this section, and in the text in general, the

determining point of each sign is the 1st degree. The use of the 8th degree

suggests a Babylonian origin,300 although in the Babylonian system the

8th degree is used at every colure point, not merely the winter solstice

(the starting point in each constellation must be the same for the formula

to be valid). Manilius has clearly garbled or misunderstood his source

material, and he has made no attempt to reconcile a clearly incorrect and

contradictory statement.

The second point is the day/night ratio of 3:2, being the 14.5 hours : 9.5

hours referred to by Manilius as occurring at the Nile Delta. This ratio

occurs at a latitude of 35 degrees north, which cuts through southern

Spain, Carthage, Sicily and Armenia, but it is not the correct figure for

Alexandria. The duration of day at the summer solstice at Alexandria

(31.5 degrees north) is 14 hours with a corresponding 10 hours of night.

There is a clear discrepancy between the ratio Manilius gives and the

correct figure for Alexandria. Goold has suggested that Rhodes (36 degrees

north) was the intended location example and that Manilius erred in referring

to the mouth of the Nile.301

It seems just as likely, however, that Manilius based his calculation on

the belief that Alexandria had both a summer solstice, day/night ratio of

3:2 and the same latitude as Babylon.302 In the Seleucid era, Babylonian

astronomers believed that Babylon was 35 degrees north, not its true


300 For a discussion of this point see Neugebauer (1975) 708–33.301 Goold (1977) 183, footnote e.302 Neugebauer (1975) 366 states that the Babylonian astrologers/astronomersbelieved that the summer solstice day/night ratio in Babylon was 3:2. This is equivalentin hours to 14 hours 24 minutes : 9 hours 36 minutes, well within what Maniliuswould have considered 9.5 hours: 14.5 hours.

latitude of 33 degrees.303 As Babylon’s true latitude is close to that of

latitude of 33 degrees.303 As Babylon’s true latitude is close to that of

Alexandria’s (31.5 degrees), Manilius may have concluded that Alexandria

also had the same ratio as Babylon. His motivation for using the Nile

Delta rather than Babylon may have been the poetic temptation to equate

the seven Delta channels with the seven planets, as one more example of

the balance and harmony he saw in his Stoic universe.

These lines present an important piece of background information, described

in detail and which, by itself, constitutes a reasonable description of the

true nature of events, not withstanding clear inaccuracies. The errors

present suggest that the description given here is a mixture of rational

explanation and confused or misunderstood material. This particular section

would explain to the analytical student what it intended, but would do so

in a confusing fashion.

6.5 First Explanation of the Principal Formula: 3.275–300

(No. 3)

This formula accounts for the obliquity of the signs to the horizon, though

it can be used for only one latitude, that of 35 degrees north (the latitude

discussed in 3.247–74). As the same formula is used later in 3.385–442,

but modified to take into account differing latitudes, it would seem that

Manilius is conforming to his didactic strategy.

The formula given is a simple table (in poetic form) listing time and

degrees, describing an incremental system that determines the rise and

set-duration of each sign, using the solstitial sign of Aries as its starting

point. The rise-duration of each successive sign east along the zodiac is


303 For a discussion of this point see Neugebauer (1975) 367. Ptolemy Geogr. 5.20.

determined and a fixed increment is added to its rise-duration until the

determined and a fixed increment is added to its rise-duration until the

equinox is reached, whereupon a fixed decremental is applied. This table

uses the fixed length hours of the preceding section (3.247–74). The

formula presumes that the increase and decrease in the rise-duration over

the course of the year changes in a strict linear function. There is no

attempt at explaining how the increments were derived. There is also the

question of the excessive accuracy displayed by the use of units as small

as stades (1/2 degree) and fractions of time as small as a minute. The

horoscope needed to be determined to within one 30 degree sign. Merely

the rise-duration in degrees would be sufficient for the determination of

the horoscope. Also the provision of the duration of each signs setting is

of complete irrelevance, since only the rise-duration is needed for the

calculation of the horoscope.

Manilius takes a measure of the credit for this formula’s origin. In lines

3.299–300, the last lines of the second formula, Manilius states that he

provided the units used in the formula.304

partibus ut ratio signo ducatur ab illo,

in quo Phoebus erit, quarum mihi reddita summa est

These units themselves are described in 3.418-9:

illa, quot stadiis oriantur quaeque cadantque.

quae quater et cum ter centum vicenaque constent.

These units are ‘stades’, each 0.5 of a degree in length, and unique in the


304 It is possible that Manilius adapted the term for this usage and is claiming to bethe first Latin author to use this measure. It is clear that the Greek astronomers usedfar smaller fractions of degrees in their research.

Astronomica. This is also the only recorded use of the term stadium for

Astronomica. This is also the only recorded use of the term stadium for

an astronomical purpose in Latin.305 It is possible that Manilius derived

the term from the Greek word .306 Apart from the question of the

term’s origin is its use, since a 0.5 degree unit has only one precedent.307

This suggests another new source for the poet.

I would conjecture that the unit was based upon the Sun and Moon: the

only permanent astronomical objects with a perceptible size, both are 0.5

of a degree in diameter. These are the astronomical bodies whose location,

along with that of the horoscope, are measured to determine the Lot of

Fortune. It is possible that this had an influence in their use here. Also,

‘ ’, suggests that stades were simply ‘points’ on star charts, i.e.

marks indicating the position of the Sun and Moon. The history and usage

of stades, in this context, is unknown.

The inclusion of ‘irrelevant’ information (set-durations) suggests that this

formula was adapted by Manilius, or by earlier astrologers, from a larger

body of work that had different goals. As the information seems irrelevant

not only to Manilius’ particular formula given here, but also to what we

know of astrological belief, it would be reasonable to conclude that the

ultimate source was astronomical.

In the field of Babylonian astronomy and astrology there are two recognised

systems for the calculation of rise and set durations, referred to as System

A and System B.308 It is a straightforward procedure to determine that the

formula used by Manilius is based upon System A. Taking the day/night


305 Oxford Latin Dictionary (1982) 1813. Elsewhere in the Astronomica Maniliususes stadium in a more conventional way, e.g. 5.162 and 5.638.306 Liddel & Scott (1940) state that can denote a ‘mathematical point’ orsomething very small.307 Neugebauer (1975) 698ff.

ratio of 9.5–14.5 hours (3.247–74) and dividing by 18 (the value for

ratio of 9.5–14.5 hours (3.247–74) and dividing by 18 (the value for

System A), the increment is 16.6 minutes. This is what Manilius would

use if he was relying on System A. The increment he does use is given in

lines 3.284–5:

hora novo crescit per singula signa quadrante

tertiaque e quinta pars parte inducitur eius

This is equivalent to 16 minutes (quarter of an hour plus the fifteenth of a

quarter of an hour—one minute). Thus the theoretical expectations of

System A and Manilius’ own formula are the same.

There are a number of other questions relating to the Babylonian origin of

Manilius’ formula. Manilius refers to the 8th degree as the determining

point for the winter solstice (3.257ff.), yet he implies that the other cardinal

points are found at the 1st point of the sign. For an accurate, or even

meaningful result, the starting point of each constellation must be the

same. As it stands (using the 8th degree), Manilius’ description would

produce a result with a 32 minute error (8 degrees by 4 minutes of time

for each degree). This usage is also made questionable by the conjecture

that System A has as its starting point the 10th degree of Aries (the vernal

equinox).309 This is doubly confusing, as System B takes as its starting

point the 8th degree. Also Neugebauer states that both System A and B

relied upon the longest day in the year as the starting point for their


308 They share a conceptual basis, in that the change in rise-duration is a progressiveincrement; however, they differ in the size and frequency of the increment over thecourse of the year. In System A, the increment is a straight mathematical addition; inSystem B, it varies geometrically. For System A, the increment is 1/18 of thedifference between the longest and shortest day. In System B, it is 1/24 of thatdifference. Multiples of each increment are added to the rise-duration of each monthto determine that of the following month. Neugebauer (1975) 712ff.309 Neugebauer (1975) 368ff.

calculations.310 Manilius uses the longest night as the starting point for his

calculations.310 Manilius uses the longest night as the starting point for his

determination of the rise-duration (3.257ff.). It is, of course, an easy task

to convert one to the other, but the incentive to do so is not stated anywhere

in the text. These apparent errors suggest that, once again, Manilius compiled

this account from a number of different sources without an equally

comprehensive effort to reconcile them.

These criticisms also call into question the relationship between 3.247–74

and 3.275–300, the first being ostensibly an introduction to the second.

This claim is partially correct. The list of rise-durations given are based

on the day/night ratio expressed in 3.247–74, but, there is no explanation

as to how the results are obtained from the introductory information. This

suggests that the source of the formula was a comprehensive document

that perhaps did explain the relationship between the ratio of day to night

and the change in rise-durations and that Manilius’ account is no more

than a mediocre summary.

Most likely, the purpose of this formula (3.275-300) is to introduce the

student to the more detailed version found in the following lines. Its

inclusion is consistent with Manilius’ didactic approach. While this

indicates an element of care and consistency in Manilius’ approach to the

work, this same care and consistency is not found in the details of this

discussion. Manilius assumes much, takes a great deal of information for

granted, and at the same time includes irrelevant information and

amalgamates sources with no attempt at reconciliation. Again we must

assume that the details of the procedures themselves were not of importance

to Manilius.


310 ibid., 713.

The use of the Babylonian formula by Manilius suggests that this usage

The use of the Babylonian formula by Manilius suggests that this usage

continued well beyond the time when it was superseded by the new, more

advanced astronomy of the Greek world. The reason for its continued use

might be found in its greater simplicity, as compared to the highly

mathematical nature of Greek positional astronomy. Also the survival of

a ‘Babylonian’ tradition in astrology well past the time when Greek

astronomy moved beyond its Babylonian origins.

6.7 Explanation of the Importance of Latitude in

Horoscope Calculation: 3.301–84 (No. 4)

Lines 3.301–84 describe the variation in the appearance of the heavens

over the course of the year and from different latitudes. They essentially

state that the preceding formula (3.275–300) is incorrect as it is valid for

only one latitude. In this the incorrect formula forms an introduction to

the following section (3.385–442), which itself provides a ‘correct’

implementation of the formula first expounded in 3.275–300.

Manilius begins this section with a three line introduction that explains

that the formula just given is incorrect. He does this by stating that that

the length of day and night varies in different lands, sed neque per terras

omnis mensura dierum / umbrarumque eadem est,...(3.301–2). This

necessarily invalidates the previous formula, which is only accurate for a

latitude with a solstice ratio, day to night of 3:2. The rise-durations vary

with latitude, as Manilius states in the following line: ...simili nec

tempora summa / mutantur: (3.302–3). Then Manilius concludes his

introduction to this section with the accurate statement that the principle

of calculation is the same, even with differing latitudes, modus est varius

ratione sub una 3.303, though he does not yet give the specific criteria.


These first three lines contain the content of this section, to explain the

These first three lines contain the content of this section, to explain the

error of the previous formula and state the basis for the following.

This account continues with a detailed description of the visibility of the

signs in each latitude beginning with the signs as seen from the equator

(3.304–22). Here, due to the path of the zodiac lying perpendicular to the

horizon, the signs, according to Manilius, rise in two hour periods, year

round. This is not entirely true. As Goold states, not all of the zodiac rises

perpendicular to the horizon,311 and those signs not on the celestial

equator would rise at an oblique angle. This factor would affect the

rise-duration of the non-equatorial signs, however, Manilius’ statement is

a fair approximation.

The remainder of this section describes the apparent effect on the rise-

duration of the signs as the observer moves away from the equator

(3.223–384). Manilius states that the zodiac will rise at a decreasing angle

to the horizon, causing a variation in the rise-duration of the signs. He

also claims that, as the observer moves north, an increasing section of the

southern sky becomes invisible behind the arc of the Earth, until, as the

north pole is approached, only six signs will be seen. He also makes the

statement that, as the observer approaches the poles, day and night will

first last 30 days each, and then, at the poles, day and night will last for 6

months. While all of these statements are correct, the point must be made

that none of this information is necessary in the calculation of the

horoscope. Only his first three lines (3.301-3), that state the necessity of

allowing for a variation in latitude, are significant in these 84 lines.

It seems that this extended description is intended to illustrate the


311 Goold (1977) 187, n. d.

limitations of the formula given in 3.275–300. In this, it is similar to the

limitations of the formula given in 3.275–300. In this, it is similar to the

discussion at 3.225ff which criticises the first formula. In this section

Manilius does again demonstrate a sound grasp of astronomical

principles, since he explains an astronomical concept (the changing

rise-durations and the variation in the length of day) clearly and

graphically for his reader.

6.8 The Principal Formula in a Version Accurate for all

Latitudes: 3.385–442 (No 5)

This version of the principal formula, first described in 3.275–300, is the

most complex and accurate. It takes into account the information

presented in the preceding section, explaining the importance of the

variation in rise-duration with latitude when determining the horoscope.

The formula is presented in two versions, one providing the results in

hours and fractions of hours, the other in, 0.5 degree units (stades). It

should be noted that these formulae stand alone, with no need for any of

the preceding formulae.

Manilius here makes a claim to the authorship of this formula, 3.393–4:

a me sumat iter positum, sibi quisque sequatur

perque suos tendat gressus, mihi debeat artem

This may be no more than a claim to have produced the Latin version of

the formula, yet Manilius does seem to take credit for the entire procedure.312


312 Manilius does state in the opening lines of Book One (1.4-5) that he is the first todiscuss these matters (astrology), aggredior primusque novis Helicona movere Icantibus.313 Neugebauer (1975) 718 mentions Hypsicles and Babylonian antecedents.

This is a clear falsehood, since the formula has clear historical antecedents.313

This is a clear falsehood, since the formula has clear historical antecedents.313

The basis of the formula is the ratio of day and night at the summer

solstice (3.396–7). This is an accurate indicator of latitude and provides a

firm basis for the calculation. This method is essentially a development of

the second formula (3.275–300) adapted for multiple latitudes. The

procedure is as follows. First determine the hours of day and night at the

solstice. One sixth of the day hours is the rise time of Leo while one sixth

of the night hours is the rise time of Taurus. This forms the starting point

for all the signs. Then divide the difference between the rise-duration of

Leo and Taurus by three. This difference, plus the rise-duration of the

previous sign, is added to each sign, beginning with Gemini and then

moving east around the zodiac until Virgo is reached (i.e. Gemini, Cancer,

Leo, Virgo). Then, we are told, Libra has the same number of hours as

Virgo (3.413), and the hours decrease by the same amount after Libra

(3.414–i.e. Libra, Scorpio, Sagittarius, Capricorn and Aquarius). This

system uses a fixed increment for each sign.

There are a number of questions raised by this description. The signs

Aries and Pisces are not mentioned. This is a curious omission. Their

rise-durations can be easily deduced from the information given, so why

not include them in the list of signs along with all the others? This level

of inaccuracy is juxtaposed with a statement by Manilius that implies a

higher level of accuracy. In 3.408–9, he explains how the rise-duration of

Leo is calculated from that of Cancer, its preceding sign. He then suggests

that the reader check Leo’s figure with that calculated earlier in 3.398–9,

where Leo’s rise-duration is calculated from the division of the longest

day. These two means of determining Leo’s rise-duration function as an

internal check on the astrologer’s calculation. This level of attention to


accuracy is at variance with Manilius’ omission of the two signs. Another

accuracy is at variance with Manilius’ omission of the two signs. Another

questionable act is the inclusion of the setting duration of the signs. As

stated above, this information is irrelevant to the calculation of the

horoscope, though Manilius includes it in both versions of this formula,

3.415–6 and 3.435–6.

This system is essentially an improved version of that given in 3.275–300,

with the addition of a modifier for latitude (the varying ratio of day and

night at the summer solstice at different latitudes). In the example given

by Manilius, one third of the difference between Leo’s and Taurus’ rising

is the increment used to determine the change in rise-duration, an increment

of 20 minutes, which is 1/18 of the difference between the longest day

and shortest night.314 This is Babylonian System A.

This is the culmination of the series of formulae and information presented

by Manilius, each more complex and accurate than the first (found in

3.247–74.) While it does include, as the first version did, such irrelevant

information as the set-duration of the signs (3.415–6), it is reasonably

accurate. This method, combined with sufficient other astronomical

information, would prove a reasonable means of determining the ‘Lot of

Fortune’ and for casting a prediction. Manilius does not, however, provide

this other information.

6.9 A Description of the Change in the Duration of Daylight

over the Course of the Year: 3.443–82. (No 6)

This section describes a formula that is irrelevant to the aim of determining

the position of the horoscope, which seems to be the object of this section


314 The ratio given for Rome is 15/9 hours. The difference of these two figures is 6hours. This, divided by 18, is 20 minutes.

of the Astronomica.315 The formula is a means to describe the increase

of the Astronomica.315 The formula is a means to describe the increase

and decrease in the length of daylight over the course of the year for any

latitude. What is the motivation for the inclusion of this formula?

The starting point for this formula is the calculation of the northern winter

solstice, the shortest day and longest night of the year. Manilius’ description

of the formula seems needlessly complex. In essence, it is necessary to

calculate one twelfth of the difference between the longest night and

shortest day. This amount is a constant, a multiple of which is added to

the duration of the first day of the following month to determine its

length. Manilius provides a formula which tells the reader the correct

multiple to use in each month. This formula predicts first the days of

winter, then spring, summer and autumn.316

Manilius not only provides the formula but also includes an example. In

3.447–82 he uses a day/night ratio of 15:9 hours, the latitude of Rome (42

degrees north), to illustrate the formula.317 Manilius could have been

influenced in his choice of ratio by a desire to cater to Roman tastes. The


315 Taifacos (1983) 146 puts forward the claim that these lines 3.443–82, are notirrelevant but essential to correct use of the final horoscope formulae of 3.385–442.His conclusion rests on the belief that a means must exist for converting ‘sundial’hours (hours of varying length) to equinoctal hours (hours of equal length). Thisargument does have an element of validity. It is necessary to use equinoctal hours inthe formula of 3.385ff. (horoscope formula), and a formula that calculates thechange in the length of daylight hours at different latitudes would be useful. Thedifficulty with his argument, however, is that the ‘rise’ formula (3.443ff.) used tocalculate this change, requires as its starting point the ratio of shortest day tolongest night—essentially, equinoctal hours—before it can calculate the variationbetween equinoctal and sundial hours. This starting point is that for the horoscopeformula (3.385ff.). So, if the astrologer has the necessary information for calculatingthe change in solar hours, as compared to equinoctal hours as required by the hourformula (3.443ff.), then this formula is not needed, as this is the same informationrequired for the horoscope formula (3.385ff.). In essence, the two formula requirethe same initial information. Thus, there is no need to include 3.443–82 in theAstronomica.

reason for the inclusion of this irrelevant formula is difficult to determine.

reason for the inclusion of this irrelevant formula is difficult to determine.

Manilius did explain the changing length of day and night in 3.247–74,

yet the calculation of the horoscope does not require this formula.

Considering Manilius’ use of astronomy and scientific imagery in general,

I feel that he may have included this formula not in order to assist in the

determination of the horoscope but to provide a guide to the student on

the changing ratio of day and night and to illustrate his own mastery of a

complex formula.

Neugebauer suggests that Manilius was using what he refers to as

Babylonian System B in this section.318 This differs from System A as

used above in two ways. The incremental difference used to calculate

successive durations of day and night is determined differently and the

frequency of increment differs.


316 The series is as follows:Capricorn - northern winter solstice, the shortest day of the year,Aquarius from which point the days grow longerPisces

Aries - northern spring equinox, days and nights are of equal lengthTaurusGemini

Cancer - northern summer solstice, the longest day of the year,Leo from which point the days grow shorterVirgo

Libra - northern autumn equinox, days and nights are of equal lengthScorpioSagittarius

The next constellation on the zodiac is Capricorn, returning the sequence to where itbegan.317 Neugebauer mentions that Ptolemy’s Almagest used eight ‘climata’ including onefor the Hellespont at 15:9 hours, (1975) 725.318 Neugebauer (1975) 722.

In the following table the actual change in ratio of day to night over the

In the following table the actual change in ratio of day to night over the

course of the year is presented along with the predicted change, as calculated

according to Systems A and B. The results indicate that both these systems

produced results accurate to fractions of an hour, accurate enough for the

time-keeping systems in contemporary use and for the purposes for which


319 As Neugebauer (1975) 714–5 points out, this is not unexpected. By a measure ofcelestial coincidence, the changing ratio of night and day and of rise-durations fits arelatively simple trigonometric formula. This apparent symmetry would have beenappealing to the Stoic sense of ‘balance’ and order in the universe.

they were intended.319

they were intended.319

Table 4: Calculation of Day/Night periods over the 12 months June

A.D. 14–May A.D. 15 at the latitude of Rome as comparing System A

& B

Column 1 2 3 4 5 6 7 8 9

Constellation date Sun Sun Duration of Right Sys A Sys B

Rise Set Day Night ascension prediction

hh.mm320 hh.mm hh.mm hh.mm of day length

hh.mm hh.mm

northern summer solstice

Cancer 23/ 6 4.37 19.37 15.00 / 9.00 6 hrs 15.00 15.00

Leo 22/ 4 4.55 19.30 14.35 / 9.25 8 hrs 14.40 14.30

Virgo 22/ 8 5.28 18.54 13.26 / 10.34 10 hrs 13.40 13.30

northern autumn equinox

Libra 23/ 9 6.04 18.02 12.00 / 12.00 12 hrs 12.00 12.00

Scorpius 25/10 6.42 17.11 10.28 / 13.32 14 hrs 10.20 10.30

Sagittarius 24/11 7.21 16.41 9.20 / 14.40 16 hrs 9.20 9.30

northern winter solstice

Capricorn 21/12 7.45 16.41 8.56 / 15.04321 18 hrs 9.00 9.00

Aquarius 17/ 1 7.44 17.05 9.20 / 14.40 20 hrs 9.20 9.30

Pisces 16/ 2 7.13 17.41 10.30 / 13.30 22 hrs 10.20 10.30

northern spring equinox

Aries 21/ 3 6.18 18.17 12.00 / 12.00 0 hrs 12.00 12.00

Taurus 23/ 4 5.23 18.49 13.30 / 10.30 2 hrs 13.40 13.30

Gemini 25/ 5 4.45 19.20 14.30 / 9.30 4 hrs 14.40 14.30


320: hh.mm is an abbreviations of hours and minutes.321 Due to the irregularities of the Earth’s orbit, the astronomical position of thewinter solstice and the position of 18 hours in right ascension are not the same. Ihave taken the 18 hour position as the determiner for this exercise and thus theperiod of day and night varies by 4 minutes.

Explanation of table

column 1

The length of daylight is calculated for the day the Sun enters each of the

twelve zodiacal signs. The twelve are divided into four groups based

upon the four tropical points.

column 2

This is the date (Gregorian calendar) when the Sun enters each constellation.

column 3 and 4

These are the times of the rising and setting Sun on those dates.

column 5 and 6

This is the length of day and night at the date given.

column 7

Right ascension is an astronomical term. In this instance, it indicates the

distance of the Sun from the beginning of Aries (each ‘hour’ equals 15

degrees).

column 8 and 9

These are the number of hours of daylight according to the formula for

Babylonian A and B.

The important columns from this table are 3, 8 and 9, the actual and the


predicted length of daylight at the beginning of each month. As can be

predicted length of daylight at the beginning of each month. As can be

seen, both Systems A and B give reasonably accurate results. The greatest

difference between the two formulae is 10 minutes, which only occurs

away from the tropical points. Although System B is more accurate giving

results that more closely match the correct figure, both systems would

provide a fair degree of accuracy.

6.10 The Second Version of the ‘Two hour’ Rise Formula:

3.483–509 (No 7)

The second version of the ‘two hour’ rise formula is the last formula in

this series. The motivation for its inclusion is unclear, on a number of

counts. Manilius has already presented a valid means of horoscope

calculation, System A (3.385–442), so no other formula is necessary. The

formula is also no more than a duplication in principle of the first formula,

that of 3.218–246, which Manilius takes great care in criticising. Its inclusion

is the most questionable part of this section of the Astronomica.322

The formula assumes that each sign takes both 2 hours and 30 degrees to

rise. As discussed above, this is a fair approximation, but it does not take

into account the variation brought about by the changing angle of the

zodiac to the horizon, which causes the rise-duration to vary. In this

version, Manilius informs the reader that each hour takes 15 degrees to

rise and that each sign, as a consequence, takes 30 degrees in rising

(3.485ff.). This horoscope formula is given in two parts and assumes that

the individual was born during the day. The first part calculates the number


322 Taifacos (1983) 149 puts forward the hypothesis that 3.483–509, as with otherlines, is an interpolation. His argument is the irrelevancy of these lines to the text.While this is not impossible I see no reason to conclude that this passage is anythingmore than another duplication, demonstrating again Manilius’ lack of concern overthe non-Stoic details of his work.

of degrees by which the beginning of the Sun’s sign is above the horizon

of degrees by which the beginning of the Sun’s sign is above the horizon

by multiplying the number of hours between the birth and sunrise by 15.

The second part of the formula adds to this first figure the remaining

degrees by which the Sun differs from the beginning of its sign. This final

figure indicates the horoscope sign. There are a number of lines missing

in this section, and according to Goold, these must have contained a brief

account of the calculation to identify the horoscope during the night.

The formula raises a number of questions. Manilius does not state if he

uses standard variable hours or his constant equinoctal hours (described

in 3.250ff.). A significant variation in the result would occur depending

on which was used.323 Also, the procedure described is not detailed enough

to be easily used by an astrologer. Manilius does not fully describe how

to allocate degrees to signs.

Goold states that this system is the same as that given earlier,324 but this is

not entirely correct. Both systems work on the same premise, but they

differ on the details. The first system (3.218–246) seems little more than

a summary prepared only to be dismissed, and it contains no details of its

operation. The second system provides greater detail, including the use of

degrees as well as hours of time. There is also evidence that this second

version was a self-contained procedure, in that it not only provides a

means to determine the horoscope (as do the earlier formulae) but also

gives the procedures to determine the subject’s fate for a day or a night

birth.


323 The standard hour would be more accurate than an incorrectly used equinoctalhour due to its variation being linked to the varying length of day/night and thus theangle of the ecliptic.324 Goold (1977) lxxvii.



The horoscope formulae illustrate the complexity of Manilius’ view of

astronomy, astrology and Stoicism. The astrological procedure described

is ostensibly intended to cast a prediction for a subject’s life, yet in this, it

is a total failure. The formulae given are too disjointed and lack sufficient

detail to achieve this end. Essentially, the Horoscope formulae are useless

as a practical astrological text. A practitioner would be puzzled by it. The

interested lay person might be impressed by the seemingly analytical

account of the procedures but would not be able to go beyond this first

impression.

One conclusion we may draw is that Manilius was not interested in providing

a detailed account of astrological procedure. In this and the other three

astrological Books (Two, Four and Five) Manilius provides a smorgasbord

of astrological methods. His intent was surely to impress the interested

lay person with his apparent mastery of such a complex subject. The

astrological descriptions were there to convince, in their complexity, that

the Stoic doctrine that supported their existence was correct. Consistently,

the discussion of astrology in the Astronomica exists merely to illustrate

the validity of Stoicism. The indifferent descriptions of astrological

procedure are understandable with this perspective, a conclusion supported

by the closing lines of Book Three. where Manilius makes a statement

that at least partially undermines his entire stated intent in Book Three. In

the context of discussing the critical importance of the cardinal points in

astrology, Manilius tells us that some astrologers variously consider the

1st, the 8th and the 10th degree of each cardinal sign to be the determining

degree (3.680–2). Manilius gives these lines without endorsing any one

of these three, though he has spent the bulk of Book Three using, in the

main, the 1st degree as the significant degree of the sign.


What these lines do clearly tell us, however, is the influence of Babylonian

astrology on its Greek counterpart. The paradigms used by Manilius in

his various formulae rely on Babylonian principles, and these therefore

suggest that he, and astrologers in general, were ignorant of the more

advanced details of Greek astronomy. Also, if Manilius was able to claim

for himself astronomical procedures already extant in Greek astronomy,

this suggests that his Roman audience were not familiar with them.

These lines provide further insight into Manilius’ didactic style. The

‘horoscope’ section contains a plethora of formulae, needlessly complex

and only moderately reconciled, but Manilius does string together a line

of discussion with examples that carries his argument forward. Beginning

with a simpler system, he explains why it is wrong and then moves onto a

more complex formula. In each case he adequately explains the errors of

the previous and justifies the move to the next. The range of sources used

argue that Manilius did, at least partially, construct these lines rather than

merely plagiarise. If this is so, Manilius was well read in astrology and

astronomy and, more than that, he understood what he read. His apparent

confusion can be explained as a lack of interest in what, to him were

unimportant details.

___________________Appendix A: Glossary of Astronomical Terms 206

Appendix A — Glossary of Astronomical Terms

The purpose of this appendix is to present a description of the various

astronomical terms used in the thesis. These definitions supplement the

brief definitions found in the text and footnotes.

Ascendant

an astrological term that refers to the sign of the zodiac or the individual

degree of a sign rising at a particular time. It is usually used to assign a

sign to a new born infant.

Atmospheric Scintillation

also known as ‘twinkling’. This occurs when astronomical objects (the

Sun, the Moon, the planets and the brighter stars) are close to the horizon,

either when rising or setting. The light from these objects passes through

thicker layers of the Earth’s atmosphere which is subject to turbulence.

This causes the light from the object to redden and appear to ‘sparkle’

with changes in colour and brightness. The colours produced by this

phenomenon are predominantly ‘reddish’.

Celestial Circles

circles projected onto the celestial sphere to mark and delimit various

representations of the paths of the planets, Sun, Moon, and the relationships

between these initial paths.

Celestial Poles


the two points (north and south) upon which the celestial sphere revolves.

the two points (north and south) upon which the celestial sphere revolves.

These are projections of the Earth’s poles on to the sky.

Celestial Sphere

a concept which describes the heavens as a sphere centred on the Earth.

This term is based upon the appearance of the sky to an observer on the

Earth’s surface.

Climata

a degree of latitude identified by the ratio of day to night at the solstices.

Comet

Comets are large (ranging in diameter from hundreds to tens of thousands

of kilometres) lumps of ice with orbits lasting from single to thousands of

years in duration. When its orbit carries a comet into the central solar

system, the heat of the Sun causes some of its icy exterior to melt, and

this results in a stream of gas trailing behind the comet. This stream of

gas glows in the Sun’s light producing a cometary ‘tail’, the size, shape

and duration of which varies greatly. A bright comet can be seen during

daylight.

Ecliptic

This is the annual path of the Sun through the sky. It forms the basis of

the zodiac.

Equinox

The point on the celestial sphere where the Sun crosses the celestial

equator. This occurs twice each year when the Sun moves from south to

north (vernal equinox, c. 21st March) and from north to south (autumnal


equinox, c. 23rd September). On the day of the equinox the length of day

equinox, c. 23rd September). On the day of the equinox the length of day

and night are equal.

See Solstice.

First Point of Aries

the intersection of the celestial equator and the ecliptic. It is used as the

zero point for the celestial positional system (analogous to the longitude

of Greenwich).

heliacal Rising

this is the first visible rising of an astronomical object in the morning sky

as the Sun moves east in its course around the ecliptic. This effect produces

the most severe scintillation—at this time the cold night air (steadily

cooling since sunset) meets the warm air heated by the rising Sun, causing

a great deal of turbulence. Thus the ‘reddest’ stars appear at their heliacal

rising.

heliacal Setting

the last visible setting of a celestial object prior to its conjunction with the

Sun.

Horoscope

the section or degree of the zodiac rising at the time of a person’s birth.

Planets

spherical bodies that revolve around the Sun in orbits ranging from months

to centuries. The Sun has nine such planets but only Mercury, Venus,

Mars, Jupiter and Saturn are bright enough to be visible from Earth with

unaided vision. These were the planets known to the ancient world.


Precession of the Equinoxes

a slow shift in the position of the celestial coordinates relative to the stars

over a period of 26,000 years. This shift is caused by the movement of

the equinox points (q.v.), which in turn is caused by a ‘wobble’ in the

Earth’s rotation.

Solstice

the point on the celestial sphere where the Sun is furthest from the celestial

equator. This occurs twice each year, first, when the Sun is furthest north

(c. 21st June), producing summer and the longest day in the northern

hemisphere (the reverse in the southern hemisphere); second, when the

Sun is furthest south (c. 22nd Dec.), producing winter and the shortest

day in the northern hemisphere (the reverse in the southern hemisphere).

See Equinox.

Appendix B

Order of constellations in Aratus’ Phaenomena and Manilius’ Astronomica

Aratus

Northern Constellations

Ursa Minor

Ursa Major

Draco

Engonasin (Hercules)

Corona Borealis

Ophiuchus

Scorpio (Zodiac)

Libra (Zodiac)

Bootes

Virgo (Zodiac)

Gemini (Zodiac)

Cancer (Zodiac)

Leo (Zodiac)

Auriga

Taurus (Zodiac)

Cepheus

Cassiepeia

Andromeda

Pegasus

Aries (Zodiac)

Triangulum

Pisces (Zodiac)

Perseus

(Pleiades)

Lyra

Cygnus

Aquarius (Zodiac)

Capricorn (Zodiac)

__________________Appendix B: Order of Constellations in Aratus and Manilius 211

Sagittarius (Zodiac)

Sagittarius (Zodiac)

Sagitta

Aquila

Delphinus

Southern Constellations

Orion

Canis Major

Lepus

Argo

Cetus

Eridanus

Piscis Australis

Hydor

Ara

Centaurus

Therium (Lupus, Bestia)

Hydra

Crater

Corvus

Canis Minor

Manilius

Zodiac

Aries

Taurus

Gemini

Cancer

Leo

Virgo

Libra

Scorpius

Sagittarius

Capricorn

__________________Appendix B: Order of Constellations in Aratus and Manilius 212

Aquarius

Aquarius

Pisces

Northern Constellations

Helice (Ursa Major)

Cynosura (Ursa Minor)

Draco

Engonasin (Hercules)

Bootes

Corona Borealis

Lyra

Ophiuchus

Cygnus

Sagitta

Aquila

Delphinus

Equus

Delton (Triangulum)

Cepheus

Cassiepia

Andromeda

Perseus

Heniochus

Southern Constellations

Orion

Canicula (Canis Major)

Procyon (Canis Minor)

Lepus

Argo

Hydra

Corvus

Crater

Centaurus

Ara

Cetus

Piscis Notius

___________________Summary of the Astronomica 213

Flumina

Flumina

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ma thesis: an examination of some aspects of the astronomica of manilius

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