At the edge of the Empire, at the turn of the millennium: glass supply and glassworking practices on the periphery of Byzantium (a case study of window glass from Veseloye, northwestern Caucasus)

The late 1st millennium AD was a period of fundamental transformations in glass production, consumption, and supply in the Mediterranean region and beyond. The data shedding light on these processes at the periphery of Byzantium are very limited so far. A church of the 10th century CE was excavated in Veseloye, in the northwestern Caucasus – the region which was under the strong cultural, economic, and religious influence of the Byzantine Empire. The chemical composition of window panes found here provides data on glass circulation and glassworking practices on the north periphery of the Byzantine world. Most of the colourless windows found here were made using plant ash glass of Levantine origin. The strongly coloured glass is of the high-boron type; it likely originated from Western Anatolia. Its compositional variability points to the complex nature of the fluxing agent, which melted with sand originating from different locations. The data obtained support the idea of several glassmaking workshops operating in parallel in Asia Minor. All the glass found in Veseloye should have been supplied to the north Caucasus through the Byzantine Empire. The peculiarities of its composition reflect the model of manufacturing window panes for the church by commission, probably in the Caucasian region. It is likely that allochthonous craftsmen worked here using imported glass. The evidence for extensive recycling has been attested for some series of high-boron glass.