Transparent high lead and tin-opacijied lead-alkali glazes have been extensively used throughout Europe and the Near East from theirjrst appearance in the Roman era and the tenth-to eleventh-century Islamic world, respectively, up until the present day. Using, to a large extent, information which is widely scattered through a diverse range of literature, the methods employed in the production of these two glaze types arejrst outlined and their merits are then compared with those of alkali glazes in terms of ease of preparation of the glaze mixture, ease of application of the glaze, ease ofjring, cost of production, glaze-body j t and visual appearance. The principal advantages of transparent high lead glazes as compared to alkali glazes are shown to be ease ofpreparation and application of the glaze suspension, low susceptibility to glaze 'crazing' and 'crawling' and high optical brilliance. Factors that influence the choice of tin-opacijied lead-alkali glazes include ease of production of tin oxide by melting tin and lead metals together; a reduced risk of reduction of lead oxide to lead metal and consequent blackening of the glaze; and, again, low susceptibility to 'crazing' and 'crawling'. Limits of current knowledge regarding these two glaze types and requirements for future research are outlined.

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87Sr/ 86 Sr ratios have been determined for glasses from four production sites, dated to between the sixth and the 11th centuries, in the Eastern Mediterranean region. On the basis of elemental analyses, the glasses at each location are believed to have been melted from different raw materials. Two glass groups, from Bet Eli'ezer and Bet She'an, in Israel, are believed to have been based upon mixtures of Levantine coastal sands and natron, and have 87 Sr/ 86 Sr ratios close to 0.7090, plus high elemental strontium, confirming a high concentration of modern marine shell ( 87 Sr/ 86 Sr ~ 0.7092) in the raw materials. The isotopic compositions of these two groups of glasses differ slightly, however, probably reflecting a varying ratio of limestone to shell because the sands that were utilized were from different coastal locations. Natron-based glasses from a workshop at Tel el Ashmunein, Middle Egypt, have 87 Sr/ 86 Sr values of 0.70794-0.70798, and low elemental strontium, consistent with the use of limestone or limestone-rich sand in the batch. High-magnesia glasses based on plant ash, from Banias, Israel, have 87 Sr/ 86 , probably reflecting the isotopic composition of the soils that were parental to the plants that were ashed to make the glass. Strontium and its isotopes offer an approach to identifying both the raw materials and the origins of ancient glasses, and are a potentially powerful tool in their interpretation.

Nineteen glasses from Maroni Petrera, Cyprus, dating to the sixth-seventh centuries AD, have been analysed by energy-dispersive X-ray analysis in the scanning electron microscope for major and minor elements. A subset of 15 glasses was also analysed for trace elements, using inductively coupled plasma mass spectrometry. Two groups are identified. The majority is made of glass produced in the coastal region of Syria-Palestine. The smaller group is of high iron, manganese and titanium (HIMT) glass, a widespread type of uncertain origin at the present time. The glasses appear to have undergone relatively minor mixing and recycling, and the glass material is likely to have arrived in Cyprus in the form of raw glass chunks or relatively fresh vessel cullet.

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