Litharge cakes from Castel-Minier (Ariège, France): understanding strategies of the cupellation in a multi metals workshop from the 14th century

Résumé En

Cupellation remains are among the most significant evidences of silver production for the Medieval period. However, these debris are rarely unearthed in archaeological context due to their fragility and their possible recycling. The exceptional corpus of cupellation remains from the metallurgical workshop at Castel-Minier (Ariège, France), dating from the XIVth century, provides the opportunity for a better understanding of the cupellation process for the late Middle Ages. Moreover, several pieces of earth lining impregnated with litharge entrapped metallic prills which were analysed using LA-ICP-MS. On the one hand our results highlight the quality of lead-silver bullion and silver produced in the workshop. On the other hand it is demonstrated how the distribution of metallic prills in the impregnated lining fragments reflects the manufacturing and recycling practices. Next, combining location of prills on linings’ surface and their elemental composition, a thermodynamic model of the cupellation in Castel-Minier is proposed. Finally, LA-ICP-MS allows measurements of trace elements which are frequently used in provenance studies (bismuth, tin, antimony). Their behaviour during cupellation is studied and their relevance as ore tracers is discussed.