In 1935 Major R. G. Gayer-Anderson Pasha, long-term resident of Cairo was permitted by the Egyptian Government to reside in one of the old Arab houses situated by the Mosque of Ibn Tulun. In fact the “house” is composed of two houses, one dating to 1041 H. / 1632 C.E., which was built by the Hajj Muhammad ibn al-Hajj Salim ibn Galman al-Gazzar. The second was built by Abd al-Qadir al-Haddad in 947 H. /1540 C. E. At an unknown date a bridge connected the two of them. While most visitors refer to the ensuing museum as the Gayer-Anderson Museum and it is so labeled by the Supreme Council of Antiquities [SCA], its more common name in Arabic is the Mathaf [Museum] Bayt al-Kritliyya.

During his residency in Bayt al-Kritliyya, Gayer-Anderson assembled collections of domestic furniture, carpets, historic artifacts and other objects representing the arts and crafts of Egypt. He had been resident in Egypt since 1907 and had retired on a pension in 1924 allowing him even greater time for his collecting. Among the objects acquired were almost 1,100 pieces of stamped glass [jetons], most in the shape of a coin with inscriptions in Arabic. In 1942 Gayer-Anderson, owing to ill health, was forced to leave Egypt, though the Egypt Government continued the tradition established by Gayer-Anderson of making his collection fully accessible to the public as well as creating in 1943 a registry of the objects in the Gayer-Anderson collection. The Egyptian Ministry of Public Instruction then converted the house and its contents into the Gayer-Anderson Pasha Museum, which in 2005 was where this project was undertaken under the supervision of the Egyptian SCA.

The project, officially entitled, A Digital Sylloge of the Islamic Stamped Glass housed in the Gayer-Anderson Museum, was undertaken by a team of four: Professor Dr. Raafat Muhammad al-Nabarawy, former Dean, College of Archaeology, Cairo University and Egypt’s leading Islamic numismatist, Mr. Sherif Sayed Anwar, Ph.D. candidate, College of Archaeology, Cairo University, Mr. Ahmed Mohammed Yousef, M.A. candidate, College of Archaeology, Cairo University, and myself.

A closer examination of our official title illuminates what we did and the ways this project differed from earlier studies of Islamic stamped glass manufactured in Egypt. First, we produced our data in a digital form rather preparing it for print in a hard copy. There were a number of advantages to this approach: first, every object was included, a point to be discussed below; second, every object could be reproduced in color, which, historically, was too expensive for printed catalogues; and third, the basic data, which included the inscription, weight and size could be available to scholars anywhere in the world. Catalogues of Islamic stamped glass tend to have small print runs, are expensive to produce and carry a high retail price, and most libraries don’t or can’t afford to acquire them. In addition, access to collections throughout the world is not always easy, particularly if one lives outside the city where the collection is housed. Using a web-based electronic publication permits anyone, anywhere access to the data.

The project is called a “sylloge” in the sense that every piece has been included. During the 20th century a few museums and collections reproduced photographs of every legible coin in their Greek or Roman collection so that scholars could study all the varieties and even possible differences between the dies from which the coins were struck. These were the firsts sylloge publications and they continue to be issued. Sylloge of Islamic coins have only been produced during the last decade and they illustrate parts of the collections of Islamic coins in Tubingen University, Tubingen, Germany and the Ashmolean Museum, Oxford, U.K. As with earlier sylloge, all the legible Islamic pieces in Tubingen and at the Ashmolean are reproduced. By scanning every Islamic stamped glass in the Gayer-Anderson Museum we have produced a sylloge of every object, not just those with legible writing, the significance of which will be noted below. In addition, this is also not a catalogue in the traditional sense in that we made no attempt to analyze the individual pieces but offer the material for scholars to do their own studies.

The term “stamped glass” or "jeton" refers to three subcategories: glass weights, vessel stamps and ring weights on which inscriptions in Arabic or, in a few cases, designs, figures, etc., have been pressed. Glass weights were used, primarily, as weight standards against which a quantity of struck gold [dinars] and silver [dirhams] and sometimes copper [fals, fulus (pl.)] were weighed since the weights of the individual coins varied significantly more than those of the glass weights. In addition, glass weights from the Umayyad and early 'Abbasid periods often included extensive data such as the name of a governor, his financial officer and the intended weight. Ring weights were inscribed stamped glass in the form of a rectangle with a hole in the center and were used for heavier measures.

Vessel stamps were created by placing a lump of molten glass on a vessel and stamping it with an iron die. This procedure tended to produce a bubble in the back of the center where the die struck, as it stayed hotter longer than the edges. Sometimes, parts of the curved vessel remained attached to the vessel stamp. Vessel stamps were used in the market to maintain weight and size standards. This also meant that vessel stamps tended to have elaborate inscriptions, which could include the name of the local governor, the local official overseeing the quality of measures, the type of product contained in the vessel such as beans, oil, herbs, alcoholic beverages, cosmetics, etc., and the size or weight of the container. Most of the scholarly work on Islamic stamped glass has focused on the pieces dated to the Umayyad and early 'Abbasid eras since they include so much historical data. The Gayer-Anderson collection has relatively few of these Umayyad and early ‘Abbasid glass weights.

While we have no data on how Gayer-Anderson acquired his glass weight collection, the way the pieces were registered offers us some clues. Almost a thousand glass weights were under one registration number and must have been kept by Gayer-Anderson as a separate collection. Whoever did the registration knew something about these pieces and could read many of them because the numbering began with the earlier Umayyad and 'Abbasid pieces followed by the more numerous Fatimid [65% of the total] and Mamluk issues [10%], although there are many exceptions to this chronological ordering.

What we did not anticipate findings was that so many of them, 18%, were illegible or in a dozen cases, totally blank never having been struck. We concluded that Gayer-Anderson couldn’t read the inscribed glass weights but treated them as just another example of Egyptian craftsmanship, which he thought should be part of his collection. We then assumed based upon their having a different registration number that Gayer-Anderson heard of vessel stamps, and bought an additional 70 stamped pieces of glass assuming them to be vessel stamps. Only half were vessel stamps while the rest were more glass weights but, this time, from almost entirely from the Umayyad and early 'Abbasid periods. Finally, we believe, again because they have a different registration number and were kept in a different location, Gayer-Anderson acquired a few fragments of ring weights to round out his collection.

Our general impression is that compared to other collections, the Gayer-Anderson holdings are very weak for the Umayyad and early 'Abbasid periods. Historic data is lacking for why this was the case. We can peculate that one or more of the following explanations were at work: the collection may reflect what was available in the Cairo; at the time Gayer-Anderson was purchasing pieces very little scholarship on glass weights had been published so he won’t have known what he owned in relation to the total range of Egyptian stamped glass, which was reinforced by his inability to read the inscriptions; and/or that local merchants passed on to him the less marketable pieces. We believe that the first explanation is the most likely one since there is very little evidence that there was a high demand for glass weights in the first half of the century unlike gold and silver coins whose metallic content added to their historic value and relatively few individuals could read the inscriptions pressed into the glass limiting market demand.

If we also assume that the collection reflected what was available in the market, then the Gayer-Anderson holdings demonstrate that during the Fatimid era, [969 – 1171, there appears to have been a relative explosion in the number of glass weights produced. Paralleling the published results of the Fatimid pieces in the Prague Museum, almost all the Fatimid glass weights, that is, 95% of all Gayer-Anderson Fatimid pieces, were struck during the reigns of the first five Fatimid caliphs, particularly during the reign of the Imam-Caliph al-Hakim bi-Amr Allah [996 - 1021] [31% of the Fatimid jetons]. Many of these Fatimid glass weights were difficult to read or illegible but after handling hundreds of them they were easily recognizable as Fatimid and, often, even associated with a particular Fatimid caliph, that is, we were reading them without “reading” the actual inscribed Arabic.

Based upon our experience in examining the Gayer-Anderson collection and its large percentage of Fatimid pieces, there may be validity to the argument that in the early Fatimid period in contrast to the earlier Umayyad and ‘Abbasid eras these glass weights served as small change in the market. Unusual pieces in the Gayer-Anderson Collection included two Tulunid jetons, a few Ayyubid examples and isolated pieces in the name of the later Fatimid iman-caliphs. Finally, the Gayer-Anderson collection demonstrates, that after a hiatus when few glass weights were produced, which coincided with the last century of Fatimid rule and most of the Ayyubid period, the Mamluk sultans [1250 - 1517] produced a number of glass weights, which were primarily characterized by the use of images and geometric designs rather than inscribed data. A systematic study of Mamluk stamped glass is still needed.

We have listed all the pieces in our sylloge by registration number since electronic searches permits searches by dynasty, ruler, governor, and even weight irrespective of what registration number has been given to the piece. Our method also allows scholars visiting the Gayer-Anderson Museum to immediately locate any piece by registration number, as we have been able with the help of Nicholas Warner to place each piece of stamped glass in its own box arranged by registration number.

Finally, there were many advantages of this project, some of which may be useful for scholars undertaking studies of other types of material housed in public museums and private collections. By having a team of four, we were able to read more inscriptions and catch more errors than if only one scholar had undertaken the project; we were able to offer Egyptian graduate students a hands-on learning experience; we were able to scan every object in a relatively short period of time when previous publications had either to rely upon plaster casts of each stamped glass or photographs of individual pieces, both of which are extremely time-consuming and costly; and, finally, we are able to make all the data including color images available to a world-wide community of scholars at no cost to them or their libraries.