Technology and materials of Early Christian Cypriot wall mosaics

Production technology of Early Christian (5th-7th centuries AD) wall mosaics, in the eastern Mediterranean and particularly in Cyprus has only recently attracted scholarly attention. Despite the numerous fragments and detached tesserae found in many sites in Cyprus with churches dated to the Early Christian period, it was only now that a more holistic technological study of the materials used for the production of these wall mosaics was initiated. Five sites were chosen for this first study: the seaside basilica of Kourion, the basilica on the acropolis of Amathous, the basilica of area EF2 at Polis-Chrysochous, the basilica of Yeroskipou - Ayioi Pente, and the two basilicas of areas II and V of Kalavasos-Kopetra. Both the glass tesserae and the plasters of the preparatory layers are discussed in this article in order to get a first insight into the technology of Early Christian Cypriot wall mosaics. XRD, DTA-TGA and mercury intrusion porosimetry were employed for the technological and compositional study of the plaster fragments. They were found to be of different compositions depending on the sites of their recovery, and may be made from local materials. Glass tesserae were compositionally characterised with the use of SEM-EDS, Raman spectroscopy, and UV-vis spectrometry. They were found to be made from different raw glass compositions compatible with the early Byzantine period, and opacified with lead stannates and tin oxide. Furthermore, some blue tesserae were found to have been opacified with calcium phosphate, probably coming from bone ash, in accordance with other, recent studies on other early Byzantine glass tesserae. The existence of colour-specific secondary workshops, hypothesised by other studies, seems to be confirmed by the results of this study.