The use of dilatometry in determining the manner of selecting ossuary vases: the case of Lugdunum during the Early Roman Empire

A recent synthesis of Lyon/Lugdunum’s ossuary ceramic ware showed that, typologically, the ceramics used to collect the residues of burnt bone were the same as those used in the city’s kitchens (Bonnet et al., 2016). The forms are indeed strictly the same. Nevertheless, some ossuary pots from the only two funerary areas known from the Augusto-Tiberian period show particular traces totally unknown on domestic ceramics, such as slits, crumbling peeled surfaces, manufacturing flaws and other characteristics suggesting insufficient firing temperature. The authors propose the hypothesis of an opportunistic use of these pots unsuitable for culinary use. In order to check if these pots were truly underfired, we have measured about thirty ossuary ceramic ware apparent firing temperatures with a dilatometer. The elemental compositions were also determined by X-Ray fluorescence spectrometry to identify the provenance of the pots. This paper will present the results of this study and offer some interpretations of the transfer of these objects from a domestic to a funerary context.