Note: The feat of carving rock crystal, an extremely hard element, was mastered by the Fatimids in the tenth century as evident from the magnificent, but limited, corpus of remaining works, including ewers, flasks and chess pieces. It was the abundant wealth of the Fatimid caliphs that permitted them to commission works of such refinement as the present chess piece. A similar example is in the Victoria and Albert Museum, London (inv. no. 669:1, 2-1883), described as “probably a king".