Analysis of Roman wall paintings and pottery from Urbs Salvia (MC, Italy)

This research project is focused on the characterization of ceramic materials and pigments from wall paintings coming from the archaeological site of the Roman city of Urbs Salvia (Macerata, Marche region, Italy). This is the first archaeometrical study obtained for the archaeological materials coming from Urbs Salvia. The archaeometrical analyses consist in the application of physical, chemical, petrographical and mineralogical methods (mainly Scanning Electron Microscopy-Energy Dispersive Spectroscopy, X-Ray Diffraction, Energy Dispersive Spectroscopy whit Mapping Analysis, optical microscopy and X-Ray Fluorescence)to obtain scientific information to complement the archaeological data, for a complete characterization and interpretation of archaeological objects. The study of the archaeological materials like pottery gives information on the life, technological abilities, cultural and economic level, commercial exchanges and routes for the populations that produce or make use of these artefacts. In particular, the study of ceramics, which represent the first materials synthetically produced by mankind, the most common material in every culture, which more specifically records the information of the cultural level reached by a population, can provide also chronological data and geographical correlations between different cultures. In the case of the ceramics from Urbs Salvia, the interest of archaeologists is mainly at determining if these materials were produced locally, which implies the presence of furnaces with specialized artisans, or if the products have a different provenance. Moreover, since scarce information is available on the technology related to the ceramic production (components, firing temperature, porosity, decoration) the mineralogical, petrographical and chemical methods have been used in this work also to address these topics. The archaeometrical study of ceramic materials from Urbs Salvia has been carried out on the common ceramic (kitchenware and tableware) because, being materials of everyday use, it is most probably of local production. The understanding of the characteristics of the local production technology and materials used in the ceramic making, allows to have a reference to be used with other ceramic types in successive studies. Sixty-four samples of different ceramic classes were analyzed with several analytical methods (Optical Microscopy, XRD, XRF, statistical methods). Regarding the ceramic materials, the characterization of Kiln Wastes allowed to define a fingerprint of the local ceramic production. Analysis shows the correspondence between Rozza Terracotta samples and Kiln Wastes, and this similarity allows to define the compositional characteristics of Rozza Terracotta ceramic class that can be considered as typical local pottery. The analysis of the Kiln Wastes allowed also to make a comparison with the Pareti Sottili samples, and the results obtained shown that the majority of the samples of Pareti Sottili ceramic class have the same characteristics of production of the Kiln Wastes and Rozza Terracotta samples. Thus it is possible to affirm that most ceramic types were made locally, although samples of imported ceramics have been identified. From the analysis of the Kiln Wastes, it is possible to differentiate two different workshops production, the first aimed at a production of coarse ceramic type, like Rozza Terracotta ceramic class, whereas the other produced a more refined ceramic production, such as Pareti Sottili. The results obtained for the ceramic samples will be used for investigating the trading routes in the Adriatic area. From the Urbs Salvia archaeological site, 34 multicolor fragment of wall paintings and 2 unused paint pellets, for a total of 47 colors analyzed, were exhaustively characterized by different analytical methods (SEM-EDS, EDS Mapping Analysis and XRD). The study of these samples does not allow to make remarks about the whole wall paintings, since they are fragments found during the excavation, but it is an useful method for the identification of pigments and mixture recipes used in the decoration of the buildings. The pigments from Urbs Salvia, never characterized before, suggest the presence of experienced artists and local workshops, with a variety of pigments and the ability of using them in a number of buildings and for a long period of time during the history of the city. The color palette of Urbs Salvia wall paintings has been found to be rich, both in terms of variety of pigments used and their preciousness. In fact, ten different pigments have been found and they include both natural and synthetic pigments, either in a pure form or in mixtures, in different proportions of two or more compounds to obtain a variety of hues and specific shades. Inexpensive and widely distributed pigments such as yellow/red ochres or green earths were recognized, as well as precious pigments such as Egyptian blue/vestorianum and cinnabar. The characterization of all the materials from Urbs Salvia, together with other archaeological and historical information, supports the idea that the city of Urbs Salvia was a rich and strategic trading center in the Roman time. A brief description of the content of each Chapter follows. Chapter 1 In this chapter an introduction on the history of the archaeological Roman site of Urbs Salvia (MC, Italy) is reported, along with the general information on the materials commonly used to get information about technology and development of an ancient roman sites: pigments and pottery. For pigments, a brief description of the most used colors in ancient time is presented. For the ceramic materials, the description and classification of the materials studied in this work are reported. Chapter 2 This chapter contains the descriptions of the materials analyzed, followed by a brief explanation of the analytical methods and experimental conditions used for the characterization of all the samples studied. Chapter 3 The experimental data and results of analysis carried out on the pigments from the wall painting samples are reported in this chapter. For the sake of simplicity the description of each pigment is reported in different sections, divided by color. Chapter 4 The experimental data and results of all the analysis carried out on ceramic samples have been reported in this chapter, which presents four different sections, divided by the analytical method used. The first part (Section 4.1) is devoted to the mineralogical analysis by XRD, whereas the results of the petrographic analysis carried out on the thin sections are reported in the second part (Section 4.2). In the third section (Section 4.3) the results of the chemical analysis by SEM-EDS and XRF are reported. The chemical data have been statistically processed, as reported in the last section of this chapter (Section 4.4). Chapter 5 This chapter contains the discussions regarding the results obtained from the characterization of pigments and ceramics. The results obtained from the pigments analyses are compared to the literature data regarding Roman pigments, whereas for the ceramics, the results obtained in this work are discussed on the basis of archaeological remarks, preliminarily proposed by archaeologists. Chapter 6 The conclusive remarks of this work are reported, in order to summarize the most important results obtained, both regarding the pigments and the ceramics.