Changes in the Supply of Glass in the Mediterranean during the First Millennium CE
Résumé
The first-millennium C.E. glass economy in the Mediterranean region was characterized on the one hand by large-scale production of raw glass in a few industrial glassmaking centers in northern Egypt and on the Levantine coast and on the other hand by a multitude of workshops where glass was remelted, colored, and formed into artifacts. This organization into primary and secondary glass production was decisively shaped by the Mediterranean trade routes that linked production sites with consumer sites. Here I discuss how changes in the trade network are reflected in the archaeological record of different Mediterranean consumer sites of the fourth to 12th centuries C.E. The analytical characterization of glass assemblages from consumer sites can shed light on the connectivity of the Mediterranean based on compositional similarities, the degree of recycling, and the experimentation with new (locally available) raw materials. Changes in the chemical makeup of eighth- to ninth-century glass assemblages appear to be the result of a downturn in long-distance trade. New glassmaking recipes and the use of alternative raw materials likewise suggest changes in the trade pattern and availability of raw materials. Specifically, we see changes in the use of alkali in the ninth century, when mineral soda, so-called natron from the Wadi Natrun in Egypt, was increasingly replaced by more locally available alkali sources such as soda- or potash-rich plant ash in the Islamic Near East and Europe, respectively. Not much is known about Byzantine glass production, yet recent analytical results from Pergamon point to a specifically Byzantine glassmaking tradition that made use of alternative sources of mineral soda in northwestern Anatolia. In this paper, I discuss analytical results of glass from diverse Mediterranean sites (Pergamon, Butrint, Carthage, San Vincenzo al Volturno) that highlight the global and regional developments in the supply of glass and raw materials as well as the underlying trade patterns during the second half of the first millennium C.E.