The Qal’a of Beni Ḥammād (medieval Algeria) and glaze technology: Technological transfers, trade and local production

• Glazed production in the Qal'a of Beni Ḥammād. • Use of tin-opacification technology in medieval Central Maghreb. • Wide range of glazing techniques and decorative methods used. • Presence of glazed ceramics produced outside of Qal’a. • New insights into the commercial and technological connections between the Hammadid capital and the Mediterranean. The Qal’a of Beni Ḥammād served as the capital of the Hammadids in the 11th century and constituted an important enclave for understanding commercial, political and economic relations in the Mediterranean and central Maghreb − present-day Algeria- during the Middle Ages. Despite its importance in the history of the central Maghreb, it is largely unknown in terms of material culture and technology. For the first time, a representative sample of glazed pottery from old archaeological excavations at the Qal’a Beni Ḥammād has been selected in order to characterise them, shed some light on their production and consumption, and to establish possible links with other Mediterranean enclaves. A ceramic assemblage is examined using a combination of microanalytical techniques (FESEM-EDS, OM, micro-XRD), including the recent discovery of a kiln rod. Two main ceramic groups have been identified, the largest of probable local production, in addition to some overseas imports. The ceramics show a wide range of glazing techniques and decoration methods, including lustre, a technical diversity which indicates the development that glazing technology had reached in the central Maghreb during the 11th C. Finally, the presence of tin oxide in the glazes to achieve opacity confirms the widespread availability and use of tin in the pottery industry during the Hammadid period.