8.4.4 Window Glass from the 1994 Excavation by C. Pamela Graves and Jody Morris

301 fragments of window glass were recovered from these excavations. This report covers the glass found on the 1994 excavations (and refers to fragments with a context prefaced with an A).

The window glass has been quantified by area since this can be related to function (Baxter and Cool 1991). The fragments were measured to the nearest 0.5cm using a 1cm grid and the results are given in square cm. There was a total of approximately 2446cm² of excavated window glass whose present condition and patterns of corrosion are consistent with medieval potash composition, that is using plant ash, usually wood ash, as a fluxing agent. Of this total, there was approximately 650cm² of painted glass (approximately 77cm² of which was unstratifed) and 1796cm² of unpainted glass. Almost all the glass is now opaque, although it would have been translucent originally. Pitting may be seen on the exterior surfaces, that is on the faces of the glass which would have been on the outside of the buildings in which the glass was set. Some examples have corroded to a sand-like consistency. All the corrosion is due to alkali being leached out of the glass possibly in situ in the buildings but mostly whilst buried in the soil. The decoration on the glass takes the form of a red/brown paint, probably iron-oxide based, and possibly containing lead. It is no longer possible to discern whether any of the glass was coloured throughout (i.e. pot-metal). No other decorative techniques were visible, such as yellow-staining, smear or stipple shading.

A small quantity of glass (31cm²) from four contexts had fire-rounded edges. These fragments are characteristic of the cylinder glass manufacturing technique (Dodwell 1961, 40-1; Harden 1961, 42; Newton and Davison 1989, 91-2). They represent the edges of complete sheets of flat glass. No indisputable evidence has come to light archaeologically for glass manufacture in the Middle Ages in Scotland. Much of it may have been imported as the Continent was the only source of coloured glass even for England for most of the period (Knowles 1936, 9; Marks 1993, passim.). From the 14th century onwards, the Exchequer Rolls of Scotland furnish evidence for the importation of glass into the ports of Blackness, Dundee and Leith, some of it recorded as intended for use in Scottish religious houses (Exchequer Rolls III, 222; IV 533 and 619; see Graves 1994, 125). Sir Robert Gordon's Genealogical History of the Earldom of Sutherland records the tradition that the glass which furnished Dornoch Cathedral in the early 13th century was made in a place called Sideray (possibly Ciderhall), two miles to the west of Dornoch (McRoberts 1970, 12). As usual with such references it is unclear whether the glass was made de novo, or whether window construction with glass made elsewhere and brought to the site is meant. A Friar John Strang, who died in the Franciscan Friary in Aberdeen, and appears in the obituary calendar of that house in 1517, was described as a very good glassmaker – vitrifaber. He supplied the whole Scottish province of the Greyfriars with glass, especially the houses in Perth, Ayr, Elgin and Aberdeen (McRoberts, 1970, 13; Bryce 1909a, 330).

The painted window glass

There is a very limited design repertoire in this assemblage. By far the majority of the painted pieces is undiagnostic, that is it is painted with single lines of paint which cannot be identified as to design or date. Only two contexts contained diagnostic painted glass: A256 and A261, both from the West Range (Trench B). Most of the painted glass is of the type known as grisaille, that is with designs of stylised foliage on either cross-hatched (A) or plain grounds (B). This glass was predominantly painted on white glass with very little colour used to alleviate the patterns, although coloured and figured panels could be set on it.

The earliest form of grisaille, using cross-hatched grounds (A), was found in context A256 [575] and A261 [595, 596]. This kind of grisaille is normally characterised by trefoils but all that is left here is the hatched ground. Some of the earliest surviving cross-hatched grisaille in Britain remains at Lincoln and Salisbury Cathedrals, dating to the first half of the 13th century, but it was used into the late 13th century. Moreover, amassing evidence from excavation proves that this was one of the most ubiquitous forms of early glazing on monastic sites, whether in Scotland, England or Wales (Graves 1994; 2000, 368-74). Samples of cross-hatched ground, without trefoils, were found previously at the Aberdeen Whitefriars site (Stones 1989, 152, Ill.93 9A).

The second datable design element from Aberdeen is composed of trefoils with small, tight heads, on long curling and crossing stems, set on plain grounds, and with bunches of three berries (B). Context A256 contained approximately 200cm² of this type [564, 565, 572), whilst context A261 contained approximately 132cm². This type of grisaille was common in the second half of the 13th/early 14th century. Examples in situ can be seen at Chartham, Kent (Winston 1867, I., 99, Cut 12; II, pl.200, and Selling Kent, c.1299/1307 (Winston 1867, II, pl.18). The Aberdeen examples have particularly small heads and the stems are unveined. Examples of the same design were found on previous occasions at the Aberdeen Carmelite Friary (Stones 1989, 152, Ill.93 1-3A). The exact form of these trefoils is so particular and characteristic that it cannot be compared with any other grisaille excavated from Scotland (cf. Graves 1994).

There is only one example of an upright, more naturalistic leaf in reserve from a solid ground [562]. This too, is most likely to be 13th century and could have formed part of a central boss decoration in a geometric arrangement of grisaille. There are two examples of a very simplified trefoil design picked out with stickwork from a matt ground: [577, 2292, 601)]. These two pieces are almost exactly the same, grozed to the same shape and may have been part of a repeated border design. No exact parallel to this has been found, but the design so clearly echoes the grisaille B found here that there can be little doubt that the two were intended to be used together. It seems possible that one fragment from previous excavations at Aberdeen is of this type also (Stones 1989, 152, Ill.93 4A).

There are only two examples of linear stickwork designs, usually associated with border patterns, used to define geometric shapes dividing up the grisaille grounds. From context A256 there is a fragment with matt wash with dots in reserve [587] and from context A261 [601] there is a fragment with matt wash and a serpentine line and circles picked out between fine painted lines. This is close to, but not the same as, the design found at Aberdeen during previous excavations (Stones 1989, 152, Ill.93 6A). These designs are both common throughout the 13th and 14th centuries.


The cross-hatched (A) and the plain grisaille (B) would, normally, represent consecutive periods of glazing, one of the early to mid 13th century, the other of the late 13th to early 14th century. There are occasions when both cross-hatched and plain grounds appear together in the same design, e.g. at Beverley Dominican Priory (Graves 1996, 133, fig.75, no.383). It is possible that the cross-hatching, which here appears to be mainly confined within simple painted lines rather than having clear evidence of trefoils, was used in bands to define geometric shapes which divided up the panels of grisaille with plain ground. Where grisaille of this second type (B) survives, it is often set with panels of figures, historiated scenes with inscriptions, and heraldry (Kerr 1983, 60). There is no evidence for these wider forms of decoration here, but the Aberdeen assemblage is very small. Since archaeologically, both the cross-hatched (A) and the plain ground grisaille (B) occur together, they may have survived in windows together, either as contemporary elements of the same design, or through deliberate reuse of older glass.

Some fragments of fire-rounded edge may be significant. If found in quantity, fire-rounded edges may represent off-cuts from glass window construction, but isolated pieces were often used as pieces of glazing themselves. Four fragments of unpainted fire-rounded edge came from Phase 5b of Area A, which has been dated to the 15th -century building and use of the West Range. As such they may represent the off-cuts from the initial fenestration programme for this range. However this context also contained some fragments of painted glass, albeit very fragmentary (155cm² of painted glass, 414cm² of unpainted glass, 716cm² altogether). Though perhaps unlikely, this does not preclude the glass as having been broken whilst glazing panels were made up for installation, if the panels were constructed on site rather than in a glazier's workshop elsewhere and brought to site complete.

However, all the painted designs from this site predate the 15th century. The same 15th –century phase contained the earliest recognised design of early-mid-13th-century grisaille on a cross-hatched ground (A), as well as the late 13th to early mid 14th-century grisaille on a plain ground (B). As such, all of this glass could represent the trample of glazing removed from some earlier building, or casual losses during refenestration of the 15th-century range. The latter implies that the glazing panels were constructed on site, but that older glass was being reused in these panels. There are recorded instances of older glazing being reused in new buildings, e.g. in the rooms of the little cloister at Beverley Dominican Priory, Yorkshire (Graves 1996, 136-7). Such reuse may have been for economic expediency, grisaille being, on the whole, cheaper than coloured glass in the first place, the reuse of older glass being cheaper still. It may have been felt that claustral buildings other than the church required predominantly white glass, such as grisaille, in order to improve visibility. An alternative explanation is that older glass was reused for deliberate iconic reasons. Twelfth-century glass was reused in the 14th-century nave clerestory of York Minster probably to assert the antiquity of the See and its political and religious claims. If the grisaille used at Aberdeen had been devoid of figural and heraldic glass, it may have been an iconic reuse in the sense that an old, austere spirituality was being emphasised at the expense of more florid, popular designs. If this were the case, it may tell us something about the Aberdeen Carmelites' attitude to spirituality.

The Carmelite Order had its origins in the eremitical tradition of the desert, but the constitution and practices of the Order were 'Dominicanised' in the mid-13th century, under the direction of St Simon Stock (King 1956, 240). From this time forth, the Carmelites may be regarded as a mendicant order, and this explains their presence in towns and cities. The new purpose and orientation of the order was approved at the second council of Lyons in 1274. The influence of the Dominicans can be seen in the Carmelite rite from this time, and in their aspirations to intellectual prowess and rigour. Such aspirations could be satisfied by the deliberate use of figureless, foliate grisaille and glass which was generally plainer than that used by some contemporary religious orders, cathedrals and parish churches (for the spiritual associations of grisaille glass see Graves 2000, 505-8). That this may have been a local decision, either on the part of Aberdeen or of the Scottish province of Carmelites in general is clear when other assemblages of Carmelite glass are considered for comparison and contrast. The Carmelite house in Newcastle upon Tyne has evidence for figural scenes being used by the 14th century (Graves 1993). The Ipswich Whitefriars has unpublished evidence for figural scenes from the 14th and 15th centuries with inscriptions, heraldry and possibly donor figures (D. Nuttall pers. com.). The most abundant material comes from the site of the wealthy Coventry Whitefriars and is mostly late 14th- and 15th-century in date, displaying ample evidence for figural representation and inscriptions. By contrast, none of the Scottish Carmelite houses have revealed any evidence for figural representation to date. The question remains as to whether this is the result of deliberate choice, economic necessity, selective use of plainer glass for claustral buildings other than the church, or an artefact of the iconoclasm of the dissolution period when figured glass may have been targetted for destruction. If such iconoclasm had occurred, with the central portions of the windows destroyed, the backgrounds patterns may have remained clinging to the sides of the windows, to drop into the soil eventually. This would certainly explain the deposits in context A256 dating to the demolition of the west range in the 16th century.

The remaining glass, painted but undiagnostic and unpainted, has limited archaeological value. There were 8.5cm² of painted and approximately 194cm² of unpainted medieval window glass from the 13th-14th-century phases of the West Range (Trenches A, B and C), i.e. at least 202cm² overall. The 15th-century building and use of the west range had at least 155cm² painted glass in total and 414cm² unpainted glass, i.e. 716cm² overall. The trenches and phasing associated with the church (Trench H) contained 6cm² of unpainted glass from the general 13th-14th-century layers and 32cm² from the 13th/14th-15th-century phases associated with the building and use of the church. Debris from the 14th-15th century church accounts for 70cm² of the unpainted glass. Post-Dissolution phases of the West Range (Trenches A, B and C) account for 363cm² of the painted glass and 585cm² of unpainted glass, i.e. 948cm² overall. The post-Dissolution phases of the Church (Trench H ) contained 23cm² of painted glass, and 181cm² of unpainted glass, i.e. 204cm² overall. It is unsurprising that the post-Dissolution phases contained the largest quantity of glass.

The fact that none of the painted glass associated with the church was diagnostic of precise date is disappointing, but the church was furnished with painted windows of some sort. The clearest evidence is for the west range which seems to have had grisaille windows which utilised older forms of design than those current in the 15th century generally. This may have been for reasons of economy; or due to the opinion that uncoloured glass was more suitable for claustral buildings than coloured glass; or for deliberate iconic use.


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