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Some problems and peculiarities of the 3D reconstruction of the late Roman fortresses in Egypt

Dmitry Karelin, Tatiana Zhitpeleva, Maria KarelinaMoscow Institute of Architecture (State Academy)

23th International Limes Congress, Ingolstadt, 13-23 September 2015

Dear colleagues. The main aim of the talk is to examine a number of questions and peculiarities considering reconstructions of late Roman fortresses in Egypt associated with their most prominent architectural features. The architectural and constructional features of Roman fortresses in Egypt can be explained and confirmed by historical reasons which could be connected with our reconstructions’ argumentation.

Architectural features reviewed in the paper:Architectural features reviewed in the paper:

1. The height of the fortresses’ walls.2 T f t hi h R d i E t2. Types of towers which Romans used in Egypt.3. Reconstructions of architectural peculiarities of gates, towers and walls:3.1. Posterns;3.2. Fortified courtyards behind the gates;3.3. Portcullises and other means of increasing the defensive potential;3.4. The distance between towers and its connection with missile

weapons.

In the presentation we review the following architectural features: 1. The height of the fortresses’ walls. 2. Types of towers which Romans used in Egypt. 3. Architectural peculiarities of gates, towers and walls: 3.1 Posterns. 3.2 Fortified courtyards behind the gates. 3.3 Portcullises and other means of increasing the defensive potential. 3.4 The distance between towers and its connection with missile weapons.

The typology of Roman fortresses in Egypt:

1. The fortresses for field army2. The fortresses for auxiliary units:2.1. The fortresses built in III – IV centuries2.1. The fortresses built in III IV centuries2.2. The fortresses built in I – III centuries in

the Eastern desert2.3. Small fortresses of IV-V centuries in the

D khl d Khoases Dakhla and Kharga3. Watch towers4. Temples-fortresses5. Rock-forts5. oc o ts

The map of Egypt with Roman fortresses of I-V centuries in Egypt

Many of the extant fortresses were built between the end of the III and the beginning of the IV century. There are, though, some exceptions - most fortifications in the Eastern Desert of Egypt were built earlier, from the I to the III century, and small fortresses of the limes in oases Kharga and Dakhla possibly were erected later, in the IV-V centuries. First of all we pay attention on the features of Later ones. All fortresses can be divided into two basic types (Карелин 2010, 154-155; Карелин 2011, 16). First - Large fortresses for field army (comitatenses) - in the Nile Delta and the Nile valley. Second - small fortresses for auxilia. The monuments are in a very bad condition (as a rule only foundations are left), so the information we have on Roman fortresses in Egypt is not sufficient for creating their reconstructions and we need to thoroughly analyse Roman military architecture of the III – IV centuries, mainly in the Eastern part of the Roman Empire.

The schematic sections of the late Roman city walls and fortresses for field army (above) and auxiliary forts (below)

First we need to consider the height of the walls and its solidity. It could vary from 4 to 11 metres from the ground to rampart walks. This difference should be explained on the three examples of fortresses with the staircases parallel to the walls - Luxor (el-Saghir et al. 1986), Babylon (Sheehan 1994; Grossmann et al. 1994, 1998; Sheehan 1996, Sheehan 2010) and Nag el-Hagar (Jaritz end Mustafa 1984-1985; Wareth and Zignani 1992; Mackensen 2009; Franke 2013). In Luxor burned brick walls could be around 5 metres (el-Saghir et al. 1986, pl. XX). Babylon's fortifications were more solid - around 11 metres (Sheehan 2010, 71, fig. 26) and were made of stones and burned bricks in opus mixtum. This ruggedness is unique for Egypt

version by P. Zignani(Wareth et al. 1992, p. 193, fig 2)(Wareth et al. 1992, p. 193, fig 2)

version by P. Grossmann(Grossmann 2003. S. 118-119)

Two variants of the walls height at Nag el-Hagar fortress

As for the walls of Nag el-Hagar, there are two points of view, both based on dimensions and configuration of the still existing staircases’ foundations and the size of lower steps. P. Zignani, supposed that the stairs led to the rampart walk from both sides, and they were about 4 metres high (Wareth and Zignani 1992, 193, fig. 2). P. Grossmann holds the opposite point of view that the stairs could lead to one side, so the wall would be twice as higher (Grossmann 2003, 118-119). P.Zignani’s version seems more probable from an architectural standpoint, because otherwise the stairs would not have led to the towers, but aside. Furthermore P.Grossman arrived at his conclusion after having examined the stairs of el-Kab, and they had a different configuration which probably indeed made the version of one-sided design of the stairs sound more possible.

Porta San Sebastiano (Porta Appia), Aurelian Walls, Rome (photo by D. Karelin, 2013)

We can find the same difference (as between Babylon and Luxor), between the first and the second phases of the Aurelian Walls in Rome - the consequence of growing threat from barbarian tribes which were gradually mastering the siegecraft or from the civil wars.

The map of the Eastern part of the Roman Empire

Besides, we can observe this difference in Roman fortresses in the Near East, for example, less solid fortifications in Arabia and very solid ones in Mesopotamia and on the Euphrates. This can be explained by the fact that fortresses in Mesopotamia and on the Euphrates had to resist the Sasanids who had advanced siege engines, while in provinces like Arabia the danger was not so great. However, we have to note that the fortresses on the border with the Sasanian Empire were constructed later, mainly in the first half of the VI century. But these examples demonstrate that the Romans used to build more massive fortresses on the borders with more serious enemy. According to J. Lander and S. Gregory (Lander 1984, 258; Gregory 1995, 149-150), such fortresses as Lejjūn, York or Luxor where legions around 2000 soldiers were quartered, did not need substantial fortifications when there was no immediate danger of attack of the enemy with advanced siege skills. Relying on this explanation we can find the reason why the Babylon’s fortifications were so massive, and also ground the hypothesis that the walls of Nag-el-Hagar and other fortresses for field army in Egypt, especially in its southern regions, used to be approximately 4 metres high. Babylon was situated at the junction of some important routes – the canal running from the Red sea and built under Trajan, the Nile and the road leading along the eastern coast of the Nile (Sheehan 2010, 65-66). Thus, Babylon stood on the way from the Sinai Peninsula to Alexandria – the port through which no less than the third of all grain was exported to Rome. When the Vandals captured Carthage, the port in the western part of the Empire almost as significant as this one, it caused the Western Roman Empire great problems. When the Muslims conquered Egypt in 641 they followed this road from Babylon to Alexandria, and Alexandria was captured only after 8 months long siege of Babylon. It seems logical to suggest that the Romans, for fear of losing Alexandria to some serious enemy, paid much attention to fortifying the key fortress on the way to the city. Other fortresses didn’t need such massive fortifications.

The schematic sections of the late Roman city walls and fortresses for field army (above) and auxiliary forts (below)

We should point out that the walls of fortresses for auxilia could be considerably taller, up to 10 metres. It can be explained by the fact that they accommodated smaller garrisons and an attack even of a small gang - could be really dangerous. Or they need to have more chambers on the small area and erected three or four storeys.

Main types of late Roman fortress towers

Let us look at other architectural features. First, there are different types of towers. Only the simplest types can be found in Egypt – that is, interval U-shaped towers and corner square towers, as well as interval square and rounded ones, which were, as a rule, common for small fortresses. Probable more effective against siege machinery round and fan-shaped corner towers were not discovered in fortress for the field army in Egypt.

Gate of the fortress at Nag el-Hagar (reconstruction by D. Karelin, based on Jaritz 1984-85, Wareth and Zignani 1999)

Secondly, we have to examine some characteristic architectural and constructional peculiarities of defensive works: First posterns in towers or walls. There were posterns at Babylon, Luxor, Nag el-Hagar and el-Kab. Second portcullises. The traces of them are quite often discovered in late Roman fortresses, but not in Egypt. They

could be in the western gate of Nag el-Hagar in the place where the passageway had a widering - they might compensate the absence of a fortified courtyard, but it is not at all indisputable (Karelin 2011, 11).

Southern gate of the fortress of Babylon (reconstruction by the authors)

But, there is one clear example - the Southern gate of Babylon. Here remained (Sheehan 2010, fig. 69) a groove for portcullises, like in some gates of the Aurelian Walls.

Third they are fortified courtyards after the first passage, which was a wide-spread technique in Roman military architecture.

In addition there are at least two examples of surviving fortified locking bars: on the southern gate of Babylon (Grossmann et al. 1994, S. 282) and in the fortress in el-Deir (Brones and Duvette 2007, pl. 12.6).

Gate of the fortress at Nag el-Hagar, cross section and elevation (reconstruction by D. Karelin, based on Jaritz 1984-85, Wareth and Zignani 1992)

Also we should pay attention to the possibly analogous spatial design of the gates of late Roman fortresses with walls 4-5 meters high (for example in Nag el-Hagar which remained only at foundation level). If we rely upon the version that rampart walk was 4 metres high and imagine that the gallery above the gate was situated at the same level then there wouldn’t be enough space for the passageway. So that the gate’s opening was high enough, the gallery would have to be situated at least 1 metre higher, and that would require some stairs.

Porta Ostiensis in Aurelian Walls, Rome. Gallery above the gate passage (photo by D. Karelin, 2013)

This type of structural organization including the stairs leading to gallery can be found in Porta Ostensis in Rome.

Towers of Babylon’s southern gate, main view, fragment of loophole and axonometric scheme (photo by D. Karelin, 2008)

Arrow slits in Umm el-Dabadib fortress: left – in northern wall, right – in the staircase of south-eastern tower (photo by D. Karelin, 2007)

The next point is parapets and arrow slits. Unfortunately, there’s only one extant parapet of Roman times – in the fortress of Maximianon (Cuvigny et al. 2003, fig. 77), which dates back to the beginning of the I – the middle of the III centuries A.D., and we can only suppose what parapets looked like on the examples from other parts of the Roman Empire which were widely studied (Baatz 1983, 136-137).

Configuration of arrow slits in Roman fortresses in Egypt is also a very interesting issue. As an example we can take the windows in the towers of the southern and eastern gate in Babylon or the bricked openings in the walls of Umm el Dabadib. We can note that, unlike arrow slits, commonly used in the eastern part of Roman Empire in the III-V centuries, these openings had practically no narrowing. However in Babylon a soldier could be protected by a wooden screen with a slit for shooting.

Scheme of the towers of a Roman fortress in Egypt with marking of the sling’s distance

The distance between towers was usually about 30 metres, which can be explained by the range of the least powerful missile weapon that the Romans used – a sling. On the other hand, such a small interval between towers, as a number of scientists suggest, is less convenient for using artillery in flanking enfilading (Gregory 1995, 151-152). This question is a very complicated one and it requires a separate study.

The typology of Roman fortresses in Egypt:

1. The fortresses for field army2. The fortresses for auxiliary units:2.1. The fortresses built in III – IV centuries2.1. The fortresses built in III IV centuries2.2. The fortresses built in I – III centuries in

the Eastern desert2.3. Small fortresses of IV-V centuries in the

D khl d Khoases Dakhla and Kharga3. Watch towers4. Temples-fortresses5. Rock-forts5. oc o ts

The map of Egypt with Roman fortresses of I-V centuries in Egypt

All the above-listed facts (minimum height of the walls, the simplest types of towers, few remaining fortified courtyards, practically absent porticullises, the distance between towers, hypothetically connected with the usage of short-range missile weapons and inconvenient for artillery, and the absence of complex fortification structures which combine different-sized towers and several contours of walls) lead to the conclusion that generally fortresses in Egypt were not intended for defence against the enemy who was advanced in siege warfare, for the exception of fortress at Babylon, and possibly Nikopolis and Pelusium. Besides, we can suggest that large fortresses in Egypt were not rebuilt, unlike, for example, the Aurelian Walls. At the same time we must note that smaller fortresses of the Libyan limes could be thoroughly rebuilt. For example the fortress of Ain Lebekha which might have acquired its final look after a number of reconstructions (Reddé 1999, 381).

THANK YOU FOR YOUR ATTENTION!THANK YOU FOR YOUR ATTENTION!

We can draw the following conclusions: The fortress of Babylon and, probably, some others situated on the way from the Sinai Peninsula to Alexandria

were so strategically important that their fortifications were outstandingly massive, as they were intended to repulse the attack of the enemy good at siege warfare.

The majority of Roman fortresses in Egypt were not meant for defence against such enemy. As Roman fortresses in Egypt are generally badly preserved, to make their reconstructions we need to carefully

examine the architecture of the surviving monuments from other parts of the Empire together with military and political tendencies which influenced forming their architectural features. And even then the reconstructions of this kind would be very hypothetical. It suggests thorough work on researching the architectural elements characteristic of the said monuments and finding as much analogies as possible. This work should result in creating of some kind of an architectural “dictionary” or a database of architectural elements and types of spatial organization.

ACKNOWLEDGEMENTS:

Funds of the Bavarian State Government (Travel Grant)Russian Foundation for Humanities (project № 14-34-01215)

Prof Dr Dmitry ShvidkovskyProf. Dr. Dmitry ShvidkovskyDr. Peter Sheehan

Dr. Cornelius von Pilgrim Staff of the libraries of Deutsches Archäologisches Institut, Kairo Abteilung

and Schweizerisches Institut für Ägyptische Bauforschung und Altertumskunde in Kairo

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