REPRINTED FROM

JOURNAL OF GLASS STUDIES

VOLUME 55 • 2013

Copyright © 2013 by The Corning Museum of Glass, Corning, NY 14830-2253

Hugh Willmott and Kate Welham

Late Seventh-Century Glassmaking

at Glastonbury Abbey

71

Glastonbury therefore remains one of the most

important production sites thus far excavated

northwest of the Alps (Fig. 1).

Despite the importance of Glastonbury Ab-

bey to early medieval studies, Radford was un-

able to publish a full account of his work, and

his most comprehensive interim report makes

little mention of the glassmaking.3 This omission

is perhaps in part due to the fact that responsi-

bility for overseeing the excavation of the ar-

chaeological remains and the subsequent analy-

sis of the artifacts was assigned to Dr. Donald

Harden, who was invited to the site when the

irst furnace was discovered in 1955. Harden

and Radford corresponded about the inds un-

til the 1980s, and although Harden compiled a

brief unpublished catalog of the artifacts, regret-

tably no details of the excavation were produced

alongside it. In 1989, Dr. Justine Bayley began

the irst comprehensive study of the surviving

rec ords and glassmaking remains. This was pub-

lished in 2000,4 and a report on the inished

products by Prof. Vera Evison appeared in the

same volume.5

GLASTONBURY ABBEY is one of the most

important early monasteries in the Brit-

ish Isles. It was founded in the late sev-

enth century in the kingdom of the West Sax-

ons (now located in the county of Somerset),

and it has been the subject of numerous exca-

vation campaigns over the past 100 years.1 The

most signiicant of these were interventions di-

rected by C. A. Ralegh Radford between 1951

and 1964, which produced substantial evidence

on the history and development of the late medi-

eval abbey and its earlier medieval predecessor.

Work undertaken by Radford over the summers

of 1955–1957 has received particular attention

from glass scholars, because it revealed the most

extensive evidence found to date for early me-

dieval glassworking in the United Kingdom. The

glassmaking site is exceptional, as it contains

not only the substantial remains of a number of

furnaces, but also a diverse range of artifacts as-

sociated with early glassworking practices. With

the exception of an unpublished example from

Barking Abbey,2 no early medieval glass furnace

in England has produced such a rich assemblage.

Late Seventh-Century Glassmaking at Glastonbury Abbey

Hugh Willmott and Kate Welham

Acknowledgments. The authors thank Prof. Roberta Gilchrist

and Dr. Cheryl Green of the Glastonbury Abbey Excavation

Archive Project Team at the University of Reading for initially

inviting them to take part in the project. We are also grateful to

Janet Bell, curator of the Glastonbury Abbey Museum, for fa-

cilitating our study, and to Dr. John Allan, archaeologist to

Glastonbury Abbey, for his comments on the pottery and cru-

cibles. Thanks are also due to Charlene Steele for taking the

photographs of the artifacts, to Jerneja Willmott for the line

drawings of the artifacts, and to Tom Cousins for the X-ray of

the blowpipe.

1. Philip Rahtz, The English Heritage Book of Glastonbury,

London: B.T. Batsford and English Heritage, 1993.

2. Kenneth MacGowan, “Barking Abbey,” Current Archae-

ology, v. 149, 1996, pp. 172–178.

3. C. A. R. Radford, “Glastonbury Abbey before 1184: In-

terim Report on the Excavations, 1908–64,” in Medieval Art &

Architecture at Wells and Glastonbury, ed. Nicola Coldstream

and Peter Draper, British Archaeological Association Conference

Transactions, v. 4, 1981, pp. 110–134.

4. Justine Bayley, “Saxon Glass Working at Glastonbury

Ab bey,” in Glass in Britain and Ireland, AD 350–1100, ed.

Jennifer Price, British Museum Occasional Paper, no. 127, Lon-

don: the museum, 2000, pp. 161–188.

5. Vera I. Evison, “The Glass Fragments from Glastonbury,”

in ibid., pp. 189–199.

72

FIG. 1. Location of early medieval monastic sites mentioned in the text.

In 2009, the Glastonbury Abbey Excavation

Project6 was created to enable the publication

and analysis of the full excavation archive. This

important initiative has provided a vital oppor-

tunity to re-evaluate all of the material relating

to the early medieval glassmaking on the site,

much of which had been unavailable to previous

researchers. A full stratigraphic and analytical

report is forthcoming,7 but this article provides

the irst comprehensive overview of the glass-

making practices that took place at the abbey.

Dating the Glass Production at Glastonbury

The glassmaking remains at Glastonbury had

been thought to consist of four furnaces located

within the area of the later medieval cloister.

Fur naces 1 (uncovered in 1955–1956) and 2

(discovered in 1956) were situated in the north-

eastern corner of the cloister (Fig. 2). Furnace 1

overlay, and presum ably replaced, Furnace 2,

largely destroying any evidence of the earlier

structure. The presence of the earlier furnace

was attested only by a patch of burned clay and

associated superstructure debris. More than 600

artifacts were recovered from this area, includ-

ing both glassworking waste and portions of the

furnace struc ture.

6. Glastonbury Abbey Excavation Project, www.reading.

ac.uk/archaeology/research/Projects/arch-RG-Glastonbury.aspx

(accessed December 19, 2012).

7. Hugh Willmott and Kate Welham, “Saxon Glassmaking,”

in Roberta Gilchrist, Glastonbury Abbey: Excavations, 1904–

1979, London: Society of Antiquaries of London, forthcoming.

73

FIG. 2. Location of furnaces within the cloister.

Furnace 3, excavated in 1956–1957, was dis-

covered to the west of Furnaces 1 and 2. Al-

though it was relatively undisturbed, there were

very few inds associated with this feature. The

reason for this paucity is unknown, but the pres-

ence of a well-preserved structure and some as-

sociated inds of vitreous slag demonstrate that

it was a glassmaking furnace. In 1957, Furnace

4 was uncovered under the western cloister

walk, and excavation in this area was conduct-

ed extremely rapidly. It is clear from Harden’s

site notebook that he was unable to positively

identify a glassmaking structure, but he inferred

that one must have been present because of the

large quantities of glassmaking waste found

there. The recent re-evaluation of the records

for this area, some of which were apparently

drawn after Harden left the site, suggests that

he encountered the tops of two diferent glass

furnaces (Furnaces 4 and 5), although neither

was fully or even partly excavated.

Although these furnaces are clearly earlier

than the Norman Conquest of 1066, their pre-

cise dating, and therefore the dating of the glass-

making phase, has always been the subject of

de bate. When discussing Furnace 1 in a letter

writ ten to Harden in December 1955, Radford

stated, “I hope next year to establish a strati-

graphical dating of pre-950, but at the moment

this is only a possibility for which there is not

suicient evidence.”8 Harden and Radford

thought that Furnaces 2 and 3 were of similar

date, but in the absence of any identiied in situ

remains, no such explicit assumption was made

for Furnace 4. Subsequent commentators have

continued to agree on a ninth- or 10th-century

date,9 with the exception of Evison, who noted

that typologically the glass was more similar

to material found on early eighth- or even late

seventh-century sites.10

As part of the Glastonbury Abbey Excava-

tion Project, a new dating program for the glass

8. Glastonbury Abbey Archive DBH01/12, letter 5.

9. See, for example, R. J. Charleston, English Glass and the

Glass Used in England, circa 400–1940, London: George Allen

and Unwin, 1984, p. 15; Rahtz [note 1], p. 92; and Bayley [note

4], p. 175.

10. Evison conceded, however, that the glass may have been

old cullet, collected to be reworked at a much later date. See Evi-

son [note 5], pp. 193–194.

74

furnaces was undertaken.11 A number of char-

coal samples from within the structures exca-

vated in 1955 were identiied, and ive of these

were selected for radiocarbon dating. Together,

they provide a broad date of 605–882, but when

the ranges of overlap are considered, a date in

the late seventh century, and the 680s in par-

ticular, can be assumed.12 This date is particu-

larly signiicant because it places the operation

of the glass furnaces in the earliest phase of

known monastic activity at Glastonbury, coin-

ciding with the reign of King Ine of the West

Saxons, who founded the monastery sometime

shortly after his accession in 688.13 Given this

association, it can reasonably be concluded that

the glassmaking operation was speciically es-

tablished to provide window glass for the new-

ly constructed buildings of the abbey, as well as

vessel glass for use by the members of the reli-

gious community.

The samples available for radiocarbon dating

came only from the area of Furnaces 1 and 2,

and so they provide a precise date for these

structures. However, because of the close simi-

larity and dating of the material culture found

in the other two areas, it seems probable that

glassmaking took place across the site in a sin-

gle, relatively short phase.

Furnace Design and Operation

Despite the identiication of ive separate fur-

nace structures at Glastonbury, any reconstruc-

tion of their original form can be based only on

Furnaces 1 and 3. Furnace 2 was destroyed by

the construction of Furnace 1, and Furnaces 4

and 5 were not suiciently excavated to provide

any details of their plan.14 Furnace 1 was oval,

measuring 1.8 m by 1.2 m externally (Fig. 3). It

was oriented on a roughly east–west alignment,

with a stokehole (W. 23 cm) on its western side,

lanked by two large stones. Harden’s plan of

the furnace shows that the outer wall was ap-

proximately 15 cm thick, although it survived

only to a maximum height of a few centimeters.

Unfortunately, this plan does not indicate how

the wall was constructed. However, a rare sur-

viving photograph in the site archive, taken

short ly after the furnace was discovered (but be-

fore it was excavated), shows a ring of tiles at

the location of the wall, suggesting that its low-

est portion was formed from clay-bonded tiles.15

The loor of the structure was a shallow depres-

sion 12 cm deep in the center. It appears, from a

description in Harden’s notebook, that the loor

was originally covered with reused Roman tiles,

11. The dating program was generously supported by a grant

from the Maltwood Fund, The Somerset and Natural History

Society.

12. A full report on the results (including discussion of the

delta 13C values and probabilities at 2 sigma) will be published

in Willmott and Welham [note 7].

13. George Norman Garmonsway, ed., The Anglo-Saxon

Chronicle, London: Dent, and New York: Dutton, 1953, p. 40.

14. A detailed stratigraphic analysis of all ive furnaces will

be provided in Willmott and Welham [note 7]. What follows

here is a summary of the key features to permit the reconstruc-

tion of the original forms.

15. National Monuments Record GLA/SITE/7.

FIG. 3. Furnace 1 (after sketch plan by Donald Harden).

75

providing a hard surface, although most of these

tiles were missing and the clay beneath had been

burned hard red. Overlying the loor was a layer

containing a considerable amount of ash and

charcoal, presumably from the inal iring, as

well as burned clay and tiles from the collapsed

or demolished superstructure. Mixed within this

were a signiicant number of glass and crucible

fragments.

Furnace 3 had a similar but more complex

form (Fig. 4). It was slightly larger than Furnace

1, measuring 2 m by 1.4 m externally, and was

built on a northwest to southeast alignment.

The outer wall survived at the northern portion

of the furnace as a layer of mortar (W. about 15

cm) resting on the clay. Although no tiles were

left in situ, it appears that this layer must have

formed the bedding and bonding for a tile-built

furnace wall. Several examples of displaced tiles

with mortar still attached were recovered from

this area of the excavation. The internal loor,

similar to that of Furnace 1, had a shallow de-

pression up to 24 cm deep in the center, but no

tiles were recovered from this layer. It is possi-

ble that they were never present, the depression

being the result of wear caused by the repeated

heating and raking-out of ashes, rather than an

intentional part of the original design.

Another feature at Furnace 3 was a stoking

or raking-out pit (1.9 m x 0.9 m) that joined the

furnace by a narrow stokehole (W. 23 cm). The

presence of a pit suggests that, unlike Furnace 1,

which was presumably built atop the external

clay surface, this furnace was slightly inset in the

ground and therefore required a pit to provide

access for the insertion of fuel and the removal

of ashes. The stokehole leading to the furnace

ap pears to have been stone-lined, and a portion

of lat stone, with evidence for mortaring on its

edges, was recovered from this area (Fig. 5). The

stoking pit, although only partly excavated, was

found to contain a signiicant quantity of ash,

charcoal, and burned material, coinciding with

its function, as well as portions of ired-clay fur-

nace superstructure. Covering the loor of the

furnace itself was another layer of burned ma-

terial and charcoal, overlain by what was de-

scribed on one section drawing as “reddened

clay including collapse of superstructure.”16

FIG. 4. Furnace 3 (after measured plan and sections

by Peter Hart).

FIG. 5. Stone with mortar on edges, recovered from

stokehole of Furnace 3 (scale 1:4).

16. Glastonbury Abbey Archive Section 16.

76

The structural remains of the furnaces, re-

tained after the excavation and still in existence

today, are detailed in Table 1. The limited re-

cording of ind locations and diiculties in dif-

ferentiating between the individual structures

experienced by the excavators have meant that

it is not always easy to attribute speciic inds

to individual furnaces, and therefore they are

grouped accordingly. Despite these challenges,

the assemblage is informative as to the original

form and construction of the furnaces. Frag-

ments of reused Roman tiles were recovered

from the excavated areas around Furnaces 1, 2,

4, and 5. Many, particularly from Furnaces 1

and 2, were not extensively vitriied, suggesting

that they may have formed parts of the core of

the lower walls of the furnaces. Others, from

both furnace areas, had surfaces that had clear-

ly been afected by prolonged exposure to heat,

and they can be presumed to have come from

the loors or perhaps the inner wall face of the

furnace. A small number of tiles also had drips

of glass adhering; blue-green and turquoise ex-

amples were recovered from Furnaces 1 and 2,

and turquoise and olive ones from Furnaces 4

and 5. These tiles were probably set in the up-

per portion of the furnaces, and in at least one

case the drip of glass adhering seems to imply

that the tile was set with its face exposed, pos-

sibly as part of the siege shelf holding the cru-

cible (Fig. 6).

FIG. 6. Tile with blue-green glass adhering, from Fur-

nace 1 or 2 (scale 1:4).

TABLE 1

Summary of Furnace Structure Retained from Excavations

Material Count Surface Furnace

Tile 15 No deposits adhering 1, 2

Tile 5 Heavily vitriied 1, 2

Tile 1 Blue-green glass adhering 1, 2

Tile 1 Turquoise glass adhering 1, 2

Aperture 9 Vitriied 1, 2

Furnace lining 12 (930 g) Vitriied 1, 2

Furnace lining 11 (324 g) Vitriied, with blue-green glass adhering 1, 2

Furnace lining 3 (20 g) Vitriied, with olive glass adhering 1, 2

Superstructure 162 (1,251 g) Fired 1, 2

Superstructure 10 (171 g) Fired 3

Tile 1 No deposits adhering 4, 5

Tile 3 Heavily vitriied 4, 5

Tile 1 Turquoise glass adhering 4, 5

Tile 2 Olive glass adhering 4, 5

Aperture 7 Vitriied 4, 5

Furnace lining 15 (683 g) Vitriied 4, 5

Furnace lining 13 (113 g) Vitriied, with blue-green glass adhering 4, 5

Superstructure 35 (803 g) Fired 4, 5

77

Finds of burned or ired clay were present in

large quantities (Table 1) and could be divid-

ed into three types: curved apertures, furnace

lining, and general superstructure. Nine frag-

ments of apertures were found in association

with Fur naces 1 and 2, and seven with Furnaces

4 and 5. These openings, crudely molded when

the clay was still wet, were irregular and always

less than 15 cm in diameter (Fig. 7). Too small

to have been portions of gathering holes, they

are thought to have probably been the remains

of vents set in the roof of the furnace to allow

hot gases to escape, and they may have been

used to regulate the internal temperature. Por-

tions of ired-clay furnace lining were also re-

covered (Fig. 8). These were characterized by at

least one smooth, highly ired face, and there

was often evidence of tile impressions on the

internal surface, suggesting that the clay was

smoothed onto the inner face of the furnace’s

tile wall as a protective covering. Furnace-lining

fragments were also found with drips of glass

on them, colored blue-green and olive from Fur-

naces 1 and 2, and turquoise and olive from Fur-

naces 4 and 5. The re maining inds of burned

clay were amorphous, but often in excess of 5 cm

thick. While some of these may have been part

of the lining, most prob ably came from the clay

roof of the furnaces.

Given the age of the assemblage and the num-

ber of the inds, any reconstruction of the orig-

inal form of the furnaces must be tentative at

FIG. 7. Aperture from area of Furnaces 4 and 5 (scale 1:6).

FIG. 8. Furnace lining from area of Furnaces 4 and 5 (scale 1:2).

78

best. However, the recently published experi-

mental work by Mark Taylor and David Hill

pro vides a useful comparison, and there are

strik ing similarities between some of their fur-

nace reconstructions and the Glastonbury evi-

dence.17 Taylor and Hill experimented with two

types of Roman-style circular furnaces, the irst

of which had tile-built walls acting as the siege,

and the second provided with a separate shelf

to hold the crucibles. The former seems to be a

closer match for the archaeological evidence at

Glastonbury, and it allows for a potential re-

construction to be proposed (Fig. 9). Furnaces

1 and 3 ofer suicient evidence of bonded tile

walls and a single stokehole, both only slightly

narrower than those used by Taylor and Hill in

their reconstructions. Another similarity with

the Glastonbury assemblage is the use of a clay-

built domed roof and what have been identiied

as small thermal vents.

There are some diferences between the Glas-

tonbury furnaces and the Roman reconstruc-

tions. Although they are of similar size, Taylor

and Hill’s furnaces were circular, while the Glas-

tonbury examples are slightly elongated and

oval. The reason for the choice of this shape is

uncertain, but it may have resulted in a more ac-

cessible working area. In the Roman reconstruc-

tions, fuel enters the furnace at a level slightly

above the loor, while at Glastonbury wood was

inserted right at the base.

One inal element recovered during the exca-

vation was possible evidence of diferent vari-

eties of wood that may have been used as fuel

for the glass furnaces. Of the charcoal samples

that were sent for radiocarbon dating, one was

from an identiiable fruitwood species (Prunus

sp.), probably cherry or plum, and two were

from the apple subfamily Maloideae, which can-

not be assigned a genus name.18 It is very like ly

that the quantities of wood to maintain the re-

quired temperature during a glassmaking cam-

paign would have necessitated the use of cop-

piced hardwoods. However, this may suggest

FIG. 9. Reconstruction of Glastonbury furnaces (drawing on Taylor and Hill [note 17]).

17. Mark Taylor and David Hill, “Experiments in the Re-

construction of Roman Wood-Fired Glassworking Furnaces,”

Journal of Glass Studies, v. 50, 2008, pp. 249–270.

18. Complete details will be found in Willmott and Welham

[note 7].

79

that all fuel was valued and that the glassmakers

were choosing to burn whatever was available

at the site. Indeed, the use of small and native

fruitwoods may indicate that the Glastonbury

furnaces burned natural vegetation that had

been cleared in the initial phase of building the

monastery.

Glassworking Practices

A comprehensive typological report on the

ves sel and window glass has already been un der-

taken by Evison,19 and therefore this is not rep-

li cated here beyond a brief summary of counts

and color variations. Regrettably, many of the

original glass and crucible fragments irst re-

cord ed by Harden and others have subsequently

been lost.20 Nevertheless, suicient material re-

mains to permit a comprehensive analysis of the

working waste and the creation of a detailed

picture of the working practices at Glastonbury.

Thirty glass crucible fragments can be identi-

ied in the assemblage, and with the exception

of a single fragment from Furnaces 4 and 5, all

of them are associated with Furnaces 1 and 2

(Table 2). The crucibles are thin-walled vessels

made from reined ball clay, and the closest

matching deposit is on the Isle of Purbeck in

Dor set, 50 miles from Glastonbury. There is an

outcrop of this clay stratum in northern France.21

Interestingly, the Glastonbury ceramic has the

same fabric as the single crucible fragment found

at the early medieval monastery at Jarrow,22 per-

haps suggesting that they had a com mon origin.

19. Evison [note 5]. Although several of the reported pieces

can no longer be identiied, no signiicant new vessel or win-

dow glass fragments have come to light, so this very thorough

report can be seen as the deinitive account of these categories

of material.

20. See Bayley [note 4], pp. 176–186. Since this report was

published, additional fragments have not been located, but

glass previously unrecorded by Harden or Bayley has become

available.

21. Data from British Geological Survey ©NERC 2013.

22. S. Mills and R. Cramp, with J. Bayley, “Crucibles and

Associated Evidence for Metal and Glass Working from Jar-

row,” in Rosemary Cramp, Wearmouth and Jarrow Monastic

Sites, v. 2, Swindon, U.K.: English Heritage, 2006, pp. 470–476.

TABLE 2

Summary of Crucibles and Waste Glass

Type Count Color Furnace

Crucible 29 Blue-green glass adhering 1, 2

Lump glass 2 Blue-green 1, 2

Lump glass 3 Blue-green glass with crucible adhering 1, 2

Lump glass 2 Mixed blue-green and turquoise 1, 2

Glass spill 1 Blue-green 1, 2

Glass moil 11 Blue-green 1, 2

Glass pull 9 Blue-green 1, 2

Glass pull 1 Emerald green 1, 2

Glass pull 4 Turquoise 1, 2

Glass rod 1 Turquoise and opaque white reticello 1, 2

Cast glass slab 1 Turquoise 1, 2

Crucible 1 Blue-green glass adhering 4, 5

Glass spill 3 Turquoise 4, 5

Glass moil 3 Blue-green glass 4, 5

Glass moil? 1 Turquoise 4, 5

Glass moil? 1 Amber 4, 5

80

All of the crucibles contain deposits of blue-

green glass, and they are often coated with sim-

ilarly colored dribbles and runs on the exterior

(Fig. 10); no other colors of glass are associated

with them. This pattern is duplicated in the inds

of lump glass, almost certainly the remains of

the melted batch, as is suggested by the portions

of crucible fabric adhering to some examples.

Exceptions are two lumps of poorly mixed blue-

green and turquoise batch from Furnaces 1 and

2, but they may represent an accidental con-

tamination rather than an intentional mixing

of colors. Finally, of the 16 moils found, all but

two are blue-green (Fig. 11), and the positive

identiication of single turquoise and amber

moils is far from certain because of their highly

fragmentary state. Consequently, it seems very

probable that only blue-green glass was melted

and subsequently blown at the site.

The delicate nature of the crucibles, coupled

with the lack of any apparent evidence for the

use of raw materials at Glastonbury, suggests

that the glassmakers were remelting fully formed

glass and cullet.23 Chemical analysis, undertaken

as part of the re-evaluation of the material,24 has

shown that most of the glass has a typical Ro-

man soda-lime-silica composition with low lev-

els of potash, conirming earlier analytical work

by Bayley and observations by Evison.25 These

analytical data also suggest that the Glaston-

bury inds derived from raw glass produced at

primary production sites in the eastern Medi-

terranean, which was likely to have been mixed

with a certain amount of recycled Roman cul-

let. It is worth noting that comparisons can be

drawn between the composition of the Glaston-

bury glass and some of the material from the

monastery at Wearmouth as characterized by

Brill.26

A small number of colored glasses are present

in the assemblage. At Furnaces 1 and 2, in addi-

tion to nine blue-green pulls (usually associat -

ed with the application of trails on vessels), one

emerald green and four turquoise examples were

found, while a spill of turquoise glass was re-

cov ered at Furnaces 4 and 5. More diagnostic

are a single surviving ind of a preformed twist-

ed turquoise and opaque white reticello rod and

a small slab of turquoise glass (formed by pour-

ing molten glass onto a hard surface before al-

lowing it to cool, leaving a roughened under-

surface) from the area of Furnaces 1 and 2 (Fig.

12). Such rods were employed only for the dec-

o ration of vessels, and a number of vessel frag-

ments found at Glastonbury were ornamented

with similar if not identical trails.27 The turquoise

23. The lack of primary glass production at Glastonbury was

suggested by Bayley [note 4], p. 174.

24. Complete details of the chemical analysis of the Glaston-

bury assemblage will be found in Willmott and Welham [note 7].

25. Bayley [note 4], pp. 172–173; Evison [note 5].

26. R. Brill, “Chemical Analyses of Some Glasses from Jar-

row and Wearmouth,” in Cramp [note 22], pp. 126–147.

27. Evison [note 5], pp. 190–191.

FIG. 10. Crucible fragment with blue-green glass de-

posit, from area of Furnaces 1 and 2 (scale 1:1).

FIG. 11. Blue-green moils from area of Furnaces 1

and 2 (scale 1:1).

81

glass slab must also be associated with the dec-

oration of vessels, since it is too thick to be a

portion of window glass. It is almost certainly

an imported ingot of colored glass, in tend ed to

be broken up and melted.

In summary, the evidence from the working

waste indicates that larger quantities of blue-

green glass were melted in crucibles for blow-

ing into vessels and windows.28 Colored glasses

were used for decoration, but they do not seem

to have been blown or even melted in the same

types of crucibles as the blue-green glass. Per-

haps it was normally suicient to heat them on

a pallet within the mouth of the furnace. This

interpretation is broadly conirmed when the

inished glass is also taken into consideration

(Table 3), although this is complicated by two

factors. First, many of the smaller fragments of

what appear to be vessel glass may, in the ab-

sence of more diagnostic features, actually be

blowing waste. It is important to note that it has

not been possible to identify any other typical

types of blowing waste in the assemblage.29 Sec-

ond, it is almost impossible to demonstrate that

a vessel or window glass fragment was deinitely

made at the site. Although it is very unlikely that

blowing waste such as moils would have traveled

far from their point of origin, the fully formed

vessels recovered may well represent collected

cullet. A little more than 200 fragments (92 per-

cent) of the fully formed glass are blue-green, al-

though many fragments have additional colors

as surface treatments.

28. Ibid.

29. For a summary of types of working waste that might be

expected, see William Gudenrath, “Techniques of Glassmaking

and Decoration,” in Five Thousand Years of Glass, ed. Hugh

Tait, London: British Museum Press, 1991, pp. 213–241; and

Hugh Willmott, A History of English Glassmaking, AD 43–

1800, Stroud, U.K.: Tempus, 2005, pp. 12–14.

FIG. 12. Turquoise and opaque white reticello rod

and turquoise slab from area of Furnaces 1 and 2

(scale 1:1).

TABLE 3

Summary of Finished Glass

Type Count Color Furnace

Uncertain 175 Blue-green 1, 2

Uncertain 4 Turquoise 1, 2

Uncertain 1 Olive 1, 2

Vessel 33 Blue-green 1, 2

Vessel 1 Emerald green 1, 2

Vessel 1 Turquoise 1, 2

Vessel 1 Red-purple 1, 2

Window 19 Blue-green 1, 2

Window 3 Amber 1, 2

Uncertain 3 Turquoise 4, 5

Uncertain 4 Amber 4, 5

Vessel 2 Blue-green 4, 5

Vessel 1 Opaque brown-red 4, 5

Window 1 Turquoise 4, 5

82

The inal unexpected and tentative evidence

for glassmaking activities at the site is the single

ind of a possible portion of a blowpipe (Fig.

13). Although this ind is heavily corroded, the

evidence of a hollow metal tube (L. 4.7 cm, in-

ternal D. about 1.0 cm) is visible by X-ray. This

is potentially signiicant because, although blow-

pipes are known from Roman and Late Antique

sites in continental Europe, no known glass-

working tools have been found in England be-

fore the later Middle Ages.30

Discussion

The recent investigation of the evidence from

Glastonbury, the irst comprehensive study of

the entire assemblage to have been made, has

revealed new insights into the nature of glass-

working at the abbey, and has begun to set this

activity into a wider technological and social

con text. Now positively dated to the late sev-

enth century, the furnaces are the earliest known

from early medieval Britain, and they are there-

fore crucial to an understanding of the develop-

ment of the post-Roman industry. Technologi-

cally, there appears to be a clear continuation

of Late Antique manufacturing traditions. The

furnaces at Glastonbury bear a striking resem-

blance to late Roman furnaces with round iring

chambers, and the construction methods em-

ployed at Glastonbury, including tile-built lower

walls and clay roofs with small apertures or

vents, mirror the experimental designs of Taylor

and Hill. It seems clear that these similarities

are not coincidental.

Compositional analysis has shown that much

of the raw glass used at Glastonbury was im-

ported from eastern Mediterranean production

centers, and that the Glastonbury glassmakers

were not simply scavenging Roman cullet. This

is to be expected, since recent isotopic research

has established that, in northern Europe, most

early medieval glass now appears to be related

in some way to large production centers discov-

ered in the Near East and the Mediterranean

30. The continental European inds are summarized in Hugh

Willmott, “Irish Glassmaking in Its Wider Context,” in Glass-

making in Ireland: From the Medieval to the Contemporary, ed.

John M. Hearne, Dublin and Portland, Oregon: Irish Academic

Press, 2010, p. 10.

FIG. 13. X-ray of possible blowpipe fragment from area of Furnaces 1 and 2 (scale 1:1).

83

region.31 It seems probable that both glassmak-

ers and glass were imported to aid in the found-

ing of King Ine’s monastery. The reference by

Bede to the arrival of Gaulish glassmakers in

675 for the establishment of the monastery at

Wearmouth is well known,32 and it is likely that

similar groups of continental European glass-

makers were brought in to work on other early

monasteries. Prof. Rosemary Cramp has high-

lighted the importance of glass used at other

late seventh- and early eighth-century monastic

sites,33 and it is clear that there was a direct re-

lationship between the reintroduction of glass

produc tion and the Roman Church in early me-

dieval England. Consequently, it is essential that

any future discussion of early medieval glass-

mak ing in England place this evidence within its

wid er European context.

31. E.g., Robert H. Brill, “Scientiic Investigations of the Ja-

lame Glass and Related Finds,” in Excavations at Jalame, Site of

a Glass Factory in Late Roman Palestine, ed. Gladys Davidson

Weinberg, Columbia: University of Missouri Press, 1988, pp.

257–294; Ian C. Freestone and Yael Gorin-Rosen, “The Great

Glass Slab at Bet She’arim, Israel: An Early Islamic Glassmaking

Experiment?,” Journal of Glass Studies, v. 41, 1999, pp. 105–

116; La Route du verre: Ateliers primaires et secondaires du se-

cond millénaire av. J.-C. au Moyen Age, ed. Marie-Dominique

Nenna, Travaux de la Maison de l’Orient Méditerranéen, no.

33, 2000; and Marie-Dominique Nenna and others, “Ateliers

primaires du Wadi Natrun: Nouvelles découvertes,” Annales de

l’Association Internationale pour l’Histoire du Verre, London,

2003 (Nottingham, 2005), pp. 59–63.

32. Charles Plummer, ed., Venerabilis Baedae historiam ec-

clesiasticam gentis Anglorum, historiam abbatum . . . , Oxford:

Oxford University Press, 1896, p. 5:368.

33. R. J. Cramp, “Anglo-Saxon Window Glass,” in Glass in

Britain [note 4], pp. 105–114.