Patterns of ceramic production in Colonia Augusta Achaica Patrensis (Patras, Greece): a petrographic and mineralogical approach

The Roman provinces did not exist as entities but as a part of a complex system involving their urban and rural landscape, communications and networks. This paper explores evidence for ceramic production within the territory of the Augustan colony of Patras, highlighting the city’s significance as a major production center due to its strategic position in regional and long-distance trading networks. Regarding the archaeological evidence, 60 sites with evidence for ceramic production were studied, providing new data on their architectural structures, workshops and kilns as well as spatial organization within Patras and its territory. The prime focus of the work, focused on the definition of local Roman wares. Hence, 150 samples were selected from the kilns and their surrounding area for typological and fabric analysis. This paper offers the first systematic archaeometric analysis of Roman ceramics from the city of Patras and serves as a major guide-line for defining what was actually produced locally (e.g. grey and red sigillatas, plain ware vessels, ceramic building materials and amphorae). Petrographic analysis enabled us to determine the local compositional patterns establishing that there are five fabrics encountered among the various workshops with few compositional differences, indicating that they derive possibly from the same locally available clay deposits. Imported (Italian) terra sigillatas could also be successfully distinguished. Mineralogical analysis through X-Ray Powder Diffraction (XRPD) allowed the study of the nature of the raw materials used and enabled the estimation of kiln firing temperatures, which ranged from 700 to 1100 °C, thereby offering vital insights into ceramic technology.