Building materials and architectural models in Late Roman Tuscany. Archaeometric studies on mortars, stones and vitreous tesserae from Villa dell'Oratorio (Florence)

In the framework of the archeological investigations of an outstanding Roman Villas in Tuscany (Villa dell‟Oratorio, in the territory of Capraia e Limite, Florence), archaeometric studies have been perfomed with the aim to characterize building and decorative materials and retrace construction phases and manufacture technology. The Villas, built in the middle of the 4th century, includes a hexagonal structure, about 30 meters in diameter, decorated with painted wall plasters and beautiful figurative floor mosaics. The structure is equipped with apsed rooms (at least 5), exhibiting similarity with some monumental triclinia of Constantinople and Rome. Archaeometric analyses have been carried out on mortars, stones and vitreous tesserae, with the aim to identify the raw materials and support the archaeological investigation about cultural models and economic status of the aristocratic owner in the Late Roman Tuscany. Mortars samples from different building units of the Villas have been studied through minero-petrographic and thermogravimetric methods. Stone tesserae have been analyzed by minero-petrographic and sedimentologic methods, to obtain information on the provenance of the raw materials used. Finally, Raman spectroscopy and SEM-EDS analyses have been performed on vitreous tesserae, to obtain information on colouring and opaquening agents. The studies carried out on the building elements suggested that, in spite of iconographic and architectural models proper of the great Mediterranean villae, local and spolia raw materials were used in this great construction work.