Beads from a mediaeval pilgrim centre: Chemical composition and provenance of glass from Banganarti, Nubia, Sudan

Abstract

Christian Nubia was a region with intensive transcultural connections that are visible through the understudied overseas glass bead imports found there. This paper presents the results of an analysis of 20 glass beads from Banganarti, a Christian pilgrim site active during the Makuria kingdom (mid-sixth to 14th centuries CE). Compositional analyses using laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS) have identified glass belonging to a number of broad compositional groups. Two beads were made of mineral soda-lime glass, dated before the mid-ninth century CE. Numerous beads were made from plant ash-soda-lime glass associated with "Mesopotamian" production dated between the eighth and 10th centuries CE. Lead-soda-silica glass has parallels in the ninth-10th centuries glass found in Africa and Europe. One plant ash-soda-lime bead was of eastern Mediterranean origin dated after the 10th century CE. Results of this study provide new evidence for provenance and chronology of glass beads available in the mediaeval Northeast Africa as well as contribute new data to the research on the pilgrim and/or trade routes of that time.

Overseas imports on the Blue Nile: Chemical compositional analysis of glass beads from Soba, Nubia

“…The Soba v‐Na‐Ca data fall also into the ‘Mesopotamian’ group that proved to contain more Cr for a given amount of Fe than the Eastern Mediterranean ones (Figure 2c). With more data from other medieval Nubian sites, which also yielded ‘Mesopotamian’ and Eastern Mediterranean glass samples, this distinction becomes even more pronounced (Then‐Obłuska & Dussubieux, 2022: Banganarti; Then‐Obłuska & Wagner, 2018: Ghazali). Additionally, some trace elements’ (Ti/Zr to Cr/La) ratios enhance the ‘Mesopotamian’ group attribution (Figure 2d).…”

“…(a) Chemical variability of the investigated beads based on K 2 O and Al 2 O 3 determination (data given as wt%); (b) biplot of Al 2 O 3 and MgO/CaO showing the results for the v‐Na‐Ca glass from Soba (see Data S1 in the additional supporting information): Banganarti (Then‐Obłuska & Dussubieux, 2022); Ghazali (Then‐Obłuska & Wagner, 2018); Serra East (Then‐Obłuska & Dussubieux, 2021b); Quseir (Then‐Obłuska & Dussubieux, 2016); Samarra 1 and 2 (Schibille et al, 2018); Raqqa, ninth century (Henderson et al, 2016); Nishapur, ninth–10th centuries (Henderson et al, 2016): Veh Ardasir, third‐seventh centuries (Mirti et al, 2008, 2009), and within range borders according to Phelps (2016); (c) biplot of Cr (ppm) and Fe 2 O 3 confirming diverse sources of the Mesopotamian and Eastern Mediterranean plant ash–soda glass for glass beads found in Soba (see Data S1); and Banganarti (Then‐Obłuska & Dussubieux, 2022); and (d) ratios of Ti/Zr to Cr/La showing different origins for the two types of plant ash–soda glass found in Soba (see Data S1); Banganarti (Then‐Obłuska & Dussubieux, 2022); and Ghazali (Then‐Obłuska & Wagner, 2018). …”

“…Among the so‐far analysed glass beads from medieval sites in Northeast Africa, those of the Mesopotamian Type 1 glass have been identified at the Upper Nubian sites of Ghazali and Banganarti and are dated to before the 12th century CE (Figures 1a and 2b–d) (Then‐Obłuska & Dussubieux, 2022; Then‐Obłuska & Wagner, 2018). Interestingly, the v‐Na‐Ca beads from the Late Ayyubid to Mamluk Red Sea port of Quseir al‐Qadim (13th–14th centuries CE) also fall into the Mesopotamian Type 1 (Figure 2b) (Then‐Obłuska & Dussubieux, 2016: tab.…”

“…Ratios of some trace earth elements, Y/Zr to Ce/Zr, and the level of Ti proved to be also useful to distinguish between the Levantine soda lime (m‐Na‐Ca) and Egyptian (m‐Na‐Ca and m/v‐Na‐Ca) glasses in both antiquity and medieval times (Schibille et al, 2018: fig. 3B; Then‐Obłuska & Dussubieux, 2022). The Egyptian glass usually features Ti levels > 415 ppm, and lower Y 2 O 3 /ZrO 2 and CeO 2 / ZrO 2 ratios when compared with glass from the Levant (> 0.15 and > 0.24, respectively) (e.g., Schibille et al, 2018; Then‐Obłuska & Dussubieux, 2021a, 2021b; Then‐Obłuska & Wagner, 2019a, 2019b).…”

“…(a) Locations of the sites mentioned in the text (map by Sz. Maślak and J. Then‐Obłuska), and the bead glass types identified in medieval Northeast Africa (Quseir: Then‐Obłuska & Dussubieux, 2016; Dongola: Dussubieux & Then‐Obłuska, 2023; Banganarti: Then‐Obłuska & Dussubieux, 2022; Ghazali: Then‐Obłuska & Wagner, 2018; Serra East and Qustul: Then‐Obłuska & Dussubieux, 2021b); and (b) glass bead samples excavated at Soba.…”