Coloured glass bracelets from Middle Byzantine (11th–12th century CE) Morava and Braničevo (Serbia)

Abstract

Forty-one samples, primarily glass bracelets, from the 11th–12th century Byzantine towns of Morava and Braničevo in Serbia were analyzed using simultaneous PIXE/PIGE. The analysis identified three types of flux: natron, plant ash, and evaporitic mineral soda. The natron glass exhibited Levantine characteristics, but extensive recycling obscured its specific group classification. Plant ash glass displayed typical compositional traits of Levantine plant ash glasses, with most samples showing evidence of recycling with natron glass. Evaporitic mineral soda glasses were traced to two distinct sources, differentiated by their boron and strontium concentrations, likely Anatolian. The evaporitic mineral soda turquoise bracelets from Braničevo resemble bracelets from Ḥiṣn al-Tīnāt in eastern Anatolia, which were produced using alkali flux derived from thermal spring evaporites. Black natron bracelets were colored with high iron concentrations. Black glasses produced from plant ash, mixed plant ash, and evaporitic mineral soda were coloured with lower iron levels in a reduced furnace atmosphere. Cobalt-blue bracelets were colored with a CoCu-type cobalt colorant, appearing in two variants: one with high zinc content, similar to the cobalt-zinc colorant found in contemporary Islamic plant ash glasses, and another with low zinc content, derived from a different cobalt ore. The diversity of raw materials sources highlights the complexity and vibrancy of Byzantine glass trade networks during the 11th–12th centuries.