(AGm 8.5, AGm 10A, AGm 4.6)
The technique of making mosaic glass was known from antiquity but it was only in the later Hellenistic period, with increasing demand for luxury glass vessels, that the technique was refined and developed into an art. The main centre of production was Alexandria in Egypt, and vessels were exported around the Mediterranean. Demand in Italy was such that during the reign of the Emperor Augustus, workshops were established in Italy. The first two items in the above lot are from 'marbled' glass bowls, made by trailing coloured and white threads together in undulating lines in imitation of banded stones, such as onyx and agate. The latter two fragments in the above lot are from ribbon-glass, made by laying strips of different colours side by side in the mould and interspersing them with transparent rods with spiral threads. Cf. D. F. Grose, Early Ancient Glass, The Toledo Museum of Art, 1989, pp. 269-277, nos. 250-284, for items 1, 2 and 4; and J. W. Hayes, Roman and Pre-Roman Glass in the Royal Ontario Museum, Toronto, 1975, p. 192. nos. 65-68.