La diffusione del vetro nell’Adriatico centrale: studi tipologici e dati chimici da Classe

The aim of this study is to identify the presence of possible glass production in the ancient harbour of Classe (Ravenna, Italy), after the redevelopment of the 5th century AD. In particular, Building no. 6 (5th–8th century) has returned a considerable number of glass objects (vessels and production wastes), probably connected with the small circular kiln identified inside. Just outside of Building no. 6, the dump US 4381 (early 6th century AD) allows a typological and compositional comparison, relative to the moment of maximum attendance of the warehouse, with the possibility of identifying which forms could be produced inside. The forms identified in the two contexts are: beakers (Is. 96, 106c and variants with rounded rim), goblets (Is. 111), bowls (Is. 116/117 and variants), lamps (Is. 134 and Uboldi III.2) and production wastes (glass chunks and working debris). The chemical analyses conducted (XRF and EPMA) show the presence of three compositional groups: HIMT glass (High Iron Manganese Titanium), Série 3.2 and Levantine I. The presence of raw glass chunks and vessels of HIMT and Série 3.2 composition can be interpreted as evidence of systematic glass-working activity in Classe, though limited to these compositions. Fragments and an absence of raw chunks, referable to the chemical group Levantine I, are in fact identified in Classe, allowing us no consideration about working activities for glass of this composition. Finally, the isotopic analyses have highlighted the likely use of coastal sands typical of the Eastern Mediterranean as raw materials, and this evidence is perfectly compatible with a secondary production (recasting of raw glass chunks and recycled materials). This study was carried out within the Italian MIUR PRIN 2009 “Continuità e discontinuità nelle produzioni vetrarie altoadriatiche tra il IX sec. a.C. e il XIV sec. d.C.”.