Composition and origins of decorated glass from Umayyad Cordoba (Spain)

Abstract

Recent archaeological excavations carried out in the western suburbs of Cordoba (Spain) brought to light numerous fragments of archaeological glass from the caliphal period (929–1031 CE). The typological and compositional analysis by laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) of 66 fragments enabled the identification of different types of base glass and glass working techniques, identifying local productions, imports and decorative imitations of eastern models. The studied fragments include Mesopotamian, Levantine, Egyptian and possibly Sicilian soda-rich plant ash glass categories, and various glass-decorating techniques such as mould-blowing, pressing, cutting, staining or gilding. The systematic comparison of the trace element patterns of several relief-cut objects identified both imported ware and a locally manufactured sample, whereas all mould-blown pieces were made from locally sourced raw materials. Iberian glassworkers seem to have preferred mould-blowing, probably because of the distinct working properties of locally available high lead glass. The results thus confirm the continuous long-distance exchange of vitreous material, as well as the existence of multiple glassmaking centres in the Iberian Peninsula, illustrating a link between secondary glass working techniques and chemical composition. Furthermore, the identification of several fragments belonging to the same object based on chemical composition allowed us to reconstruct entire vessels and thereby expand the repertoire of known typologies circulating in Umayyad Spain.

Islamic Glass in the Making

“…The dwellings where the glass objects were found were built in the middle of the tenth century and destroyed sometime in the first third of the eleventh century; thus these assemblages are roughly contemporary with Madīnat al-Zahrā'. Indeed, the samples show exactly the same compositional features: high concentrations of soda and magnesia and moderate levels of potash, as well as relatively low concentrations of lime and remarkably high chlorine contents (De Juan Ares et al 2021). Trace elements associated with the source of lead (Ag, Sn, Sb, Bi) again indicate the use of litharge in the production of these soda-ash lead glasses, rather than slag as was the case at Šaqunda.…”

“…(a) Silica and lead oxide levels illustrate different mixing ratios, with silica lead glasses at the high PbO end of the spectrum and central European potash lead glasses at the high silica end; (b) potash and soda contents reflect the use of different raw materials for silicalead glasses, potash-lead glasses and soda-ash lead glasses; (c) iron versus aluminium oxides highlight the distinctive nature of the high-lead glass from Šaqunda displaying a similar trend to the high-lead smoothers from Melle in France. Data sources: (Gratuze et al 2003) for smoothers; (De Juan Ares et al 2021) for soda-ash lead glass from Córdoba; (Bergmann et al 2008;Brill 1999;Kuisma-Kursula and Räisänen 1999;Mecking 2013;Wedepohl et al 1995; for central European potash lead glasses; for Islamic silica lead glasses; (Schibille et al 2020a) for Šaqunda.…”

“…It is these soda-ash lead glasses that constitute more than 70% of the vitreous material in the palatial city of Madīnat al-Zahrā', as well as about 50% of tenth-to eleventh-century glass assemblages from domestic contexts in Córdoba (De Juan Ares et al 2021;. "From Polis to Madina" and the flux of glass in Spain Domestic assemblages in Córdoba and the advent of Iberian plant ash glass About half of the tenth-century glass recovered from residential areas of a western suburb of the medieval city of Córdoba known as Picinas Municipales de Poniente (PMP) is also a soda-ash lead glass (De Juan Ares et al 2021). This confirms earlier observations that this type of glass is typical of the caliphal city .…”

Recipientes islámicos de vidrio dorado encapsulado: evidencias en al-Andalus

“…No obstante, los estudios sobre vidrio andalusí han sido hasta la fecha escasos, entre los que cabe destacar los volúmenes colectivos editados por P. Cressier (2000) y E. Rontomé (2006). En los últimos años, dicha deficiencia está siendo subsanada por el creciente interés de estos materiales para la reconstrucción de los patrones tipológico-tecnológicos de esta clase de manufactura y su implicación económica y social dentro de la población andalusí (De Juan y Schibille, 2017; De Juan, Cáceres y Schibille, 2018;De Juan et al, 2021;Duckworth et al, 2015;Govantes-Edwards et al, 2016;Govantes-Edwards, López y Duckworth, 2020;Schibille et al, 2020).…”

“…(Granada), añadiendo otras referencias a dos ejemplares publicados (De Juan et al, 2021;Carmona, Moreno y González, 2008) hallados en el ya citado arrabal noroccidental cordobés.…”