Loose glass tesserae and lost decorations: chronology and production of mosaics from Gerasa's Northwest Quarter*

Abstract

Laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) analyses of loose glass tesserae from the Northwest Quarter of Gerasa/Jerash has enhanced our understanding of the dynamics regulating the production and circulation of glass tesserae in second-to eighth-centuries CE Jordan and the diachronic development of mosaics at the site. The identification of Levantine and Egyptian compositions (Roman-Mn, Levantine I, HIMT, Foy 2.1) proves the continuous production of mosaics from the second to the seventh centuries. The Levantine I tesserae were made by the recycling and colouring of glass cullet. The gilded tesserae, in contrast, were all of an Egyptian base glass, likely illustrating the import of finished tesserae.

Glass in Rome during the transition from late antiquity to the early Middle Ages: materials from the Forum of Caesar

“…Four samples may be Foy 2.1 or similar. One decolourised gold leaf tessera (CF 046) appears to represent Levantine I type glass from Apollonia, despite its elevated Mn levels that is probably related to the colouring of the glass to modify the shade of the gold foil [58] (Fig. 6b).…”

Hunting colours: origin and reuse of glass tesserae from the Wierum terp

“…The presence of the colourless, aqua and naturally coloured glass in the collection must be due to the recycling of Roman glass, as these types of glass were widely used in Roman windowglass, glass vessels and tableware. A recent study reveals that in Byzantine Jordan from the sixth century onwards there was also a shortage in raw glass procurement and that colourless glass was systematically collected and reused (Boschetti et al 2021). Recycling of blue-green Roman glass is also seen in the West, for instance at San Vincenzo where blue-green window glass, presumably taken from a nearby Roman building, was recycled in the ninth century for the production of vessel and window glass in the monastery (Schibille and Freestone 2013).…”

A Tale of Two Legacies: Byzantine and Egyptian Influences in the Manufacture and Supply of Glass Tesserae under the Umayyad Caliphate (661–750 AD)

“…As, contrariwise, Foy-2 and Apollonia-type glass are recurrent in Umayyad assemblages of mosaic tesserae, this fact could support the hypothesis of tesserae recovered from dismantled sites, previously adorned with mosaics, rather than freshly made. [55,56]; Ravenna, 6th century [57][58][59][60][61][62][63]-site tag is filled in a different way because, in the references, the base glass is generically termed Levantine rather than Levantine I; Durres, 6th-8th century [44]; Constantinopole, 6th century [64]; Hierapolis, 6th century [43]; Amorium, 10th century [65]; Tyana, 5th century [66]; Kilise Tepe, 5th-6th century [43]; Huarte, 5th century [67]; Cyprus, 6th century [38]; Petra, 5th-6th century [68,69]; Jerash, 4th-8th century [70].…”

“…Maps with the indication of sites where tesserae containing (a) Sn-based and/or Pb-Snbased phases and (b) P-based phases have been detected. References: Jerash, 4-8th century[70]; Kilise Tepe, 5-6th century[43]; Durres, 6-8th century[44]; Istanbul, 6th century[64]; Cyprus, 6th century[38]; Sagalassos, 6th century[89]; Amorium, 10th century[65]; Hierapolis[43]; Huarte, 5th century[67]; Petra, 5-6th century[68,69]; Tyana, 5-6th century[66]; Naples, 4-9th century[90]; Rome, 16th century[91]; Florence, 13-14th century[92]; Ravenna, 5-6th century[57][58][59][60][61]; Padua, 6th century[55,56]; Milan, 5-6th century[93]; Aquileia, 4th century[73].…”