Supply of glass to the medieval hilltop settlement of Ultrera (Eastern Pyrenees, France)

International audienceFounded in the fifth century on a granite outcrop overlooking the deep valleys of the eastern Massif des Albères and the Roussillon coast, the hilltop settlement of Ultrera/Ultrère was strategically located to dominate the lowlands. Its position on this natural boundary between the Iberian Peninsula and Central Europe raises interesting questions about its connectivity and the circulation of materials. In the early days of rural feudalism, the emergence of the castrum led to the birth of the "feudal" castle and the first fortified villages. Ultrera was organized into several districts spread over three hectares and survived until the tenth century CE, which is an exceptionally long occupation. The present paper examines the glass supply to Ultrera throughout its history, combining typological and archaeometric approaches to study the evolution of glass compositions and the use of different raw materials through time. A series of 43 well-contextualized glass objects have been analysed for major, minor and trace elements using LA-ICP-MS. The glasses of the fifth to seventh centuries comprise mostly vessels and especially goblets. The base glass can be affiliated to previously established natron-type primary production groups (HIMT, Foy 2.1, Foy 3.2 and Levantine 1), and about half of it shows substantial signs of recycling. The ninth-to tenth-century assemblage marks a change from the previous occupation. Two beads made from a soda-rich plant ash glass confirm Islamic imports from Mesopotamia and perhaps the western Mediterranean. A linen smoother with a wood ash glass signature is the only testimony of Carolingian influences. Glass tableware is becoming increasingly rare and some of the drinking goblets are remnants from a previous phase. The progressive independence of the Catalan counties from the Carolingian Empire and the change of the glass production system towards the end of the first millennium CE may explain the absence of typical Frankish glass. Soda plant ash glass from the thirteenth and fourteenth centuries, probably from the feudal castle, indicates yet another change at the end of the Middle Ages, when there is evidence for both regional production and long distance imports