The carpet is of eastern origin and in general can be said to differ from tapestry by the technique of its knotted weave. The refined technique and ornate geometrical patterns found on fragments discovered in eastern Turkestan, dating from the 5th and 6th centuries A.D., indicate a long evolution in the history of the carpet. ---- The Abbasid caliphs of Baghdad were also well-known patrons of carpet manufacture: one made for Caliph Hashin early in the 8th century measured 100 yards by 50 yards. The most famous area of production was, however, northwestern Persia.