BUILDING MATERIALS AND ARCHITECTURAL MODELS IN LATE ROMAN TUSCANY. ARCHAEOMETRIC STUDIES ON MORTARS, STONES AND VITREOUS TESSERAE FROM “VILLA DELL’ORATORIO” (FLORENCE)

Abstract

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.