Glass import and production in Hispania during the early medieval period: The glass from Ciudad de Vascos (Toledo)

Abstract

One hundred and forty-one glass fragments from medieval Ciudad de Vascos (Toledo, Spain) were analysed by laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS). The glasses fall into three types according to the fluxing agents used: mineral natron, soda-rich plant ash, and a combination of soda ash and lead. The natron glasses can be assigned to various established primary production groups of eastern Mediterranean provenance. Different types of plant ash glasses indicate differences in the silica source as well as the plant ash component, reflecting changing supply mechanisms. While the earlier plant ash groups can be related to Islamic glasses from the Near East, both in terms of typology and composition, the chemical signature of the later samples appear to be specific to glass from the Iberian Peninsula. This has important implications for our understanding of the emerging glass industry in Spain and the distribution patterns of glass groups and raw materials. The plant ash that was used for the Vascos glasses is rich in soda with low levels of potash, similar to ash produced in the eastern Mediterranean. It could therefore be possible that Levantine plant ash was imported and used in Islamic period glass workshops in Spain. Unlike central and northern Europe where an independent glass industry based on potassium-rich wood ash developed during the Carolingian period, the prevalence of soda ash and soda ash lead glass on the Iberian Peninsula indicates its commercial and technological interconnection with the Islamic east. Our study thus traces several stages leading to the development of a specifically Spanish primary glassmaking industry.

The Supply of Glass at Portus Ilicitanus (Alicante, Spain): A Meta‐Analysis of HIMT Glasses

“…). On the Iberian Peninsula, HIMT has likewise been found in fourth‐ and fifth‐century contexts in Portugal, Galicia, Alicante, Catalonia, Extremadura, Madrid, Cuenca, Valencia, Murcia, Leon and Seville (De Juan and Schibille ,b and references therein).…”

“…Even though, from a typological point of view, the materials do not seem to postdate the first half of the fifth century, there are a few samples for which a date in the first decades of the sixth century cannot be ruled out (Table S1). Hence, our new analytical data address the supply of late Roman glass to the Iberian Peninsula at the time when glass compositions diversified (De Juan and Schibille ,b). To resolve the networks of exchange, we compared the analytical results from Picola with the compositional data of contemporary glass assemblages.…”

The Chronology of Insiza Cluster Khami‐Phase Sites in South‐Western Zimbabwe: Compositional Insights from pXRF and Raman Analysis of Excavated Exotic Glass Finds

“…A mixture of sand and Levantine ash in the manufacture of glass is reported from sites dated from the 10th century to the 16th century in Ciudad de Vascos (Spain), Silves (Portugal), Tuscan and Savona (Italy) (Cagno et al . , ; de Juan Ares and Schibille ). Among these sites, samples from Vascos are earlier (mid‐11th century to early 12th century) than this assemblage.…”

“…The alumina content is remarkably high for most of the European plant‐ash glasses manufactured after the 10th century ad , except those that were manufactured in Italy, Spain and Portugal (Cagno et al . ; Coutinho ; de Juan Ares and Schibille ). The glasses in these regions were manufactured by using local high‐impurity sand and plant ash from the Levant, Spain, France and Tunisia (Malandra ).…”

“…Similar mixtures of local sand and ashes from the Levant and the Western Mediterranean have been reported from Silves, Coimbra and Tarouca (Portugal), Tuscan and Savona (Italy) (Cagno et al . , ; de Juan Ares and Schibille ). Based on the available data (composition and date), the European beads of this assemblage (group 2) are closer to the glasses from Tuscany, Savona, Coimbra and Tarouca, while more accurate measurements of trace elements are necessary to determine the exact source of the beads.…”