<P> For most of the Middle Ages Islamic glass was the most sophisticated in Eurasia, exported to both Europe and China . Islam took over much of the traditional glass - producing territory of Sassanian and Ancient Roman glass, and since figurative decoration played a small part in pre-Islamic glass, the change in style is not abrupt, except that the whole area initially formed a political whole, and, for example, Persian innovations were now almost immediately taken up in Egypt . For this reason it is often impossible to distinguish between the various centres of production, of which Egypt, Syria and Persia were the most important, except by scientific analysis of the material, which itself has difficulties . From various documentary references glassmaking and glass trading seems to have been a speciality of the Jewish minority in several centres . </P> <P> Between the 8th and early 11th centuries the emphasis in luxury glass is on effects achieved by "manipulating the surface" of the glass, initially by incising into the glass on a wheel, and later by cutting away the background to leave a design in relief . The very massive Hedwig glasses, only found in Europe, but normally considered Islamic (or possibly from Muslim craftsmen in Norman Sicily), are an example of this, though puzzlingly late in date . These and other glass pieces probably represented cheaper versions of vessels of carved rock crystal (clear quartz), themselves influenced by earlier glass vessels, and there is some evidence that at this period glass cutting and hardstone carving were regarded as the same craft . From the 12th century the industry in Persia and Mesopotamia appears to decline, and the main production of luxury glass shifts to Egypt and Syria, and decorative effects of colour on smooth surfaced glass . Throughout the period local centres made simpler wares such as Hebron glass in Palestine . </P> <P> Lustre painting, by techniques similar to lustreware in pottery, dates back to the 8th century in Egypt, and became widespread in the 12th century . Another technique was decoration with threads of glass of a different colour, worked into the main surface, and sometimes manipulated by combing and other effects . Gilded, painted and enamelled glass were added to the repertoire, and shapes and motifs borrowed from other media, such as pottery and metalwork . Some of the finest work was in mosque lamps donated by a ruler or wealthy man . As decoration grew more elaborate, the quality of the basic glass decreased, and it "often has a brownish - yellow tinge, and is rarely free from bubbles". Aleppo seems to have ceased to be a major centre after the Mongol invasion of 1260, and Timur appears to have ended the Syrian industry about 1400 by carrying off the skilled workers to Samarkand . By about 1500 the Venetians were receiving large orders for mosque lamps . </P> <P> Medieval Islamic metalwork offers a complete contrast to its European equivalent, which is dominated by modelled figures and brightly coloured decoration in enamel, some pieces entirely in precious metals . In contrast surviving Islamic metalwork consists of practical objects mostly in brass, bronze, and steel, with simple, but often monumental, shapes, and surfaces highly decorated with dense decoration in a variety of techniques, but colour mostly restricted to inlays of gold, silver, copper or black niello . The most abundant survivals from medieval periods are fine brass objects, handsome enough to preserve, but not valuable enough to be melted down . The abundant local sources of zinc compared to tin explains the rarity of bronze . Household items, such as ewers or water pitchers, were made of one or more pieces of sheet brass soldered together and subsequently worked and inlaid . </P>

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