Technological evolution of roman green-glazed pottery: a comparative archaeometric study between centuries

Abstract

This study investigates the composition of Roman lead-glazed pottery from the Constantinian Basilica at Ostia Antica, analyzing 14 samples from the 1st to the 4th century C.E. by SEMEDS, XRD, and ATR-FTIR. Glazes are primary PbO-SiO2 systems with lead as a flux, copper, iron, and cobalt can be added as colorants, and calcium/antimony oxides used as opacifiers. Compositional variations suggest multiple recipes and galena-derived Pb saucers. Microstructural features indices single-firing productions. Crystalline phases such as diopside and anorthosite point to a firing temperature of around 700- 950 ªC. Dolomite and calcite are present in the ceramic body, indicating calcareous clay and align with Lazio region geology, implicating local manufacture. Statistical tests (Shapiro-Wilk, Multivariate Graphical Analysis) reveal heterogeneity, indicating the possibility of different workshops