The glazes of early Islamic pottery of the 8th to 12th centuries and from various sites in Mesopotamia, Egypt, notheastern Persia and Turkestan, and Turkey have been analyzed by microscopic and chemical investigations using the electron microprobe technique. Several types of glazes have been established and their relation to those of the preceding historical periods as well as their influence on the glaze techniques of the later Islamic periods during the following centuries could be shown.