Several glass mosaic tesserae were found during the archeological excavations at the Villa di Teodorico in Galeata (Forlì-Cesena, Emilia Romagna, Italy), dated to early sixth century AD. This work reports the results of an archeometrical investigation realized through a multi-technique approach on 16 tesserae. The aims of the study were the determination of the glass composition, the characterization of coloring and opacifying agents, and the definition of the technological processes involved. The glass matrix and the dispersed crystallites were characterized in detail through micro-Raman spectroscopy, field emission scanning electron microscopy with energy-dispersive X-ray spectroscopy, and X-ray powder diffraction analyses. Micro-Raman spectroscopy was proven to be very effective in the analysis of complex objects, providing information on the structure and composition of the glass and on the nature of the opacifying agents and the crystalline colorants. UV-visible-NIR diffuse reflectance spectrophotometry with optic fibers was helpful to identify the metal ions used as chromophores. The different hues were obtained by means of dispersed ions as well as crystalline compounds and metal nanoparticles. A large variety of opacifying agents was detected. Results were compared with data of contemporary mosaics within the same geographical area.

We report a new fossil-bearing locality from the “Chaotic Complex” units in the Northern Apennine Chain of the Emilia-Romagna Region (northern Italy). The material collected includes an articulated series of nine caudal vertebrae referable to a large-bodied ichthyosaur. Based on the nannofossil assemblage sampled from the matrix encasing the vertebrae, we refer the specimen to the early Aptian: this is the first accurate chronostratigraphic dating of a Cretaceous ichthyosaur from the Apennine Chain. The discovery of this new fossil-bearing locality is also significant because of the rather poor record of Aptian ichthyosaurs worldwide. Compared to the large majority of vertebrate remains from the “Chaotic Complex” units, usually represented by isolated or damaged skeletal elements, the specimen retains several vertebral elements in articulation and is associated to ichnological traces left by possibly saprophagous invertebrates, a taphonomic pattern which might indicate depositional conditions less destructive than those usually assumed for the genesis of the “Chaotic Complex’’ vertebrate fossils. The presence of both ichthyosaurs and thalattosuchians in the Aptian of Italy supports the persistence in the Western Tethys of the large-bodied pelagic reptile clades typical of the Middle and Late Jurassic along the first half of the Early Cretaceous.

Villa di Teodorico in Galeata (Forlì-Cesena, Emilia Romagna) is an important archeological site in the north of Italy occupied from sixth century BC to twelfth century AD. The most interesting results concern the Roman age, when a large villa was built, and the late antiquity, when the Ostrogothic king Theodoric decided to build in this area his palatium (early sixth century AD). The archeometric investigation was performed on Roman wall paintings fragments and on late antique glass sectilia fragments belonging to Palazzo di Teodorico by using a multi-technique approach that included micro-Raman spectroscopy, scanning electron microscopy with energy-dispersive spectroscopy, X-ray powder diffraction, UV–visible–NIR diffuse reflectance spectrophotometry with optic fibers and optical stereo-microscopy.. This analytical approach allowed the identification of all components, collecting molecular, elemental, microscopic, morphological and chromatic data. The characterization of samples supplied essential archeological, historical and technological information. The production techniques and the rich materials employed suggest the importance of the site in different periods. The evolution of the manufacturing technologies and the possible trade routes mainly during late antique period are witnessed by the change in the raw materials. Graphical abstract