The proportion of lead in ancient glazes is higher than in modern lead glazes. Probably such high proportions of lead were deliberately used in order to obtain glazes that melted at conveniently low temperatures. The presence of high proportions of lead might possibly be a useful index for distinguishing between genuine ancient lead glazed ware and modern forgeries or imitations of such ware. The composition of Roman glazes from Tarsus is of decided interest for the history of ceramic glazes in general. Writers on the history of ceramics make contradictory statements as to the time when lead glazes were first introduced. Some state explicitly that lead glazes did not come into use until the twelfth century A.D. Others give various earlier dates. The lack of concrete evidence in the form of careful chemical analyses of dated specimens of ancient glaze sufficiently accounts for this confusion. Only a few specimens of ancient lead glaze have been identified as such by scientific tests and for the most part these were of uncertain provenance. Most identifications of ancient lead glaze appear to have been made on the less reliable basis of physical appearance alone. The present analyses establish beyond a doubt the use of lead glazes in Asia Minor in Roman times.