The transition from Roman to Late Antique glass: new insights from the Domus of Tito Macro in Aquileia (Italy)

The present paper focuses on the archaeological, chemical and isotopic characterisation of glass finds from the Domus of Tito Macro (former Domus dei Fondi Cossar) in Aquileia (Italy), dated between the 1st and the 7th century AD. The assemblage comprises both vessels and glassworking residues, including a few chunks. Aims of the study are the identification of the main glass compositions and their contextualisation in Roman and Late Antique reference groups, and of provenance of primary glass. Chemical analyses were conducted by XRF and EPMA. All the analysed fragments are silica-soda-lime glasses, produced with natron as a flux, and are compositionally similar to the Roman coloured (intentionally and unintentionally) and colourless (antimony-, manganese-, and antimony þ manganese-decoloured) groups and to the Late Antique groups HIMT, Serie 3.2 and Levantine 1. Specific compositional traits of HIMT glass circulating in the north-Adriatic area and a scarcity of Levantine 1 glass are evidenced. The presence of rare HIT blue glasses including a chunk suggests that colouring took place also at primary stage of production. Sr and Nd isotopic analyses, performed on a selection of samples, confirmed the eastern Mediterranean origin of the glasses, although with minor internal differences depending on the compositional group. Chemical and isotopic data suggest a continuity between the Roman and Late Antique glassmaking in terms of sand deposits and sand/flux ratio, although with a major change in the decolouring technique after the 4th century AD. The prompt reception of the Late Antique glass compositions took place in Aquileia alongside the persistence of earlier compositions, probably with the aim of satisfying different segments of the glass market.