Beyond Bibracte/Mont Beuvray: regional traditions and raw glass supply of red enamels in La Tène and Roman Central Europe

Abstract

This paper presents a compositional study of red enamels applied to metal artefacts from Central Europe, spanning the La Tène period (4th − 1st centuries BCE) to the Roman period (1st − 3rd centuries AD). The dataset comprises 107 enamel samples from Bohemia, Moravia, south-western Slovakia, Lower Austria and Styria, complemented by reference material (11 samples) from the oppidum of Bibracte/Mont Beuvray (France), the only site in Europe with direct archaeological evidence for enamel production in the La Tène period. Chemical compositions, including trace elements, were determined using LA-ICP-MS. All analysed enamels are soda–lime–silica glasses, frequently enriched in lead and copper. Based on K₂O and MgO contents, all La Tène enamels are natron-based, while Roman-period samples show greater compositional variability. Provenance assessment using Zr, Sr concentrations and trace-element ratios (Y₂O₃/ZrO₂ and CeO₂/ZrO₂) indicates that most Central European La Tène enamels differ from those produced at Bibracte/Mont Beuvray (France), reflecting distinct technological traditions and, in many cases, different sources of raw glass. Although Levantine natron glass dominates the assemblage, a smaller group of enamels – mainly dated to the Middle La Tène period – exhibits characteristics consistent with Egyptian glass. The results demonstrate both continuity in the use of lead- and copper-rich red enamels into the Roman period and significant changes in raw glass supply and decolourising practices. Overall, the study provides new insights into regional organisation of enamel production and long-distance glass circulation in Iron Age and Roman Central Europe.