Production technology of late Roman decorated tableware from the Vesuvius environs: Evidence from Pollena Trocchia (Campania region, Italy)

The northern slope of Mt. Vesuvius contains some interesting archaeological sites, including the site discovered in the town of Pollena Trocchia, where the remains, dated to between the 79 and 472 CE eruptions, document the transition from the Roman to late Roman cultural and socioeconomic settings. Profound changes occurred in this time interval, which can be inferred from changes in the ceramic manufacturing processes. Common wares, as the most widespread ceramic class in the archaeological record, are a useful example that illustrates this technological transformation. Seventeen samples of tableware, distinguished into three ceramic classes according to the method of slip application (i.e., Slipped Ware, Painted Ware “a straccio,” and Painted Ware), were analyzed. The results highlight the use of high-CaO clayey raw materials compositionally similar to Apennine clayey deposits. The clay bodies were occasionally tempered with sandy-silt materials composed of volcanic grains with lesser amounts of siliciclastic fragments. Firing temperatures ranged from 800 to 950°C, as suggested by quantitative X-ray powder diffraction and microstructural analyses combined with colorimetric measurements of the ceramic bodies. Micro-Raman analyses performed on slips revealed the use of ochre for decorating the vessels; it was applied in a different way, representing an actual technological change.