From tin- to antimony-based yellow opacifiers in the early Islamic Egyptian glazes: Regional influences and ruling dynasties

Abstract A representative selection of early Islamic glazed ceramics from Egypt, with yellow and/or green as major colours and spanning the period from 8th to 11th centuries has been studied. Following the production of Coptic Glazed Ware in 8th century, in which lead stannate was used to produce an opaque yellow glaze side by side with brown and green transparent lead glazes, the lead stannate opaque yellow appears to have been lost in Egypt by the second half of the 9th century when new shapes were produced consequence of the Abbasid Iraqi influence. However, by the 10th century, polychrome glazed ceramics were being produced in the Fustat region using lead antimonate in the production of yellow, amber and green glazes which were applied side by side. At the same time, tin oxide began to be used for the production of opaque white and turquoise glazes. It is suggested that the rediscovery of lead antimonate was a result of experimental firings of available minerals, such as stibnite or a galena with stibnite impurities. Finally, with the Fatimid conquest of Egypt in 969 CE and the foundation of Cairo as the dynasty capital, the tradition for producing ceramics with yellow and green decoration over a white background spread from Ifriqiya (Tunisia) to Egypt. However, in Ifriqiya, the glazes were transparent and a whitened clay body provided the background whereas, in Egypt, lead antimonate was used for the yellow, and tin oxide for the white glaze which provided the background. From Egypt, the latter glaze technology spread to Tunisia, and from there to other Mediterranean regions. In conclusion, it is argued that the political and historic events in Egypt and the wider Islamic world seem to have provided the main driving force for the observed changes in both ceramic style and glaze technology.