• burial
• diagenesis
• embalming
• multi-analytical approach
• Roman Empire

This thesis presents the development and the principal results of a multi analytical approach dedicated to the characterisation of organic and inorganic materials recovered from three archaeological burials. The principal aim of this research was the identification of the preserved materials to understand their function in these funeral structures.
The archaeological materials studied come from the catacomb of Saints Peter and Marcellinus in Rome where numerous bodies were simultaneously pilled up together and from two French sites located in Anché and Naintré where the bodies were contained in lead coffins. All sites, originating in the Roman Empire, are dated to the second-third century AD.
The experimental part of the thesis was organised into three parts. First, the samples were observed and classified on the basis of their morphological features. Then, their analysis by FTIR spectroscopy allowed to obtain a first chemical identification. Finally, on the basis of the results obtained by FTIR spectroscopy, separative, structural and other spectroscopic techniques were implemented to enlarge knowledge relative to the nature and the state of degradation of each material. This multi-analytical protocol, optimised for the study of minute samples, allowed to identify a large range of materials such as resinous substances, dyes, minerals and textiles and provided new information, at a molecular level, about the processes of degradation of these materials in archaeological context.
The association of archaeological data with chemical information allowed to understand the function of most of the materials present into the tombs. It demonstrated the use of clay and precious imported resins to embalm the bodies. The presence of gypsum and calcite established that all bodies were packed, an unusual funeral practice at this time.
The same analytical protocol applied to anthropological materials, such as bones and skin fragments, shed new light on the diagenesis of human remains in their archaeological environment.
From an historical point of view, this research revealed new elements about the rich funeral practices of the Roman Empire and increases knowledge about the technical know-how of the period, such as textile manufacture and purple dyeing. Moreover, new information about the exchanges of precious materials such as Baltic amber, frankincense and oriental textiles at this time was obtained.