caliph

noun

the chief Muslim civil and religious ruler, regarded as the successor of Muhammad. The caliph ruled in Baghdad until 1258 and then in Egypt until the Ottoman conquest of 1517; the title was then held by the Ottoman sultans until it was abolished in 1924 by Atatürk.

late Middle English: from Old French caliphe, from Arabic ḵalīfa meaning ‘deputy (of God’) (from the title ḵalīfat Allāh ), or meaning ‘successor (of Muhammad)’ (from the title ḵalīfat rasūl Allāh ‘of the Messenger of God)’, from ḵalafa ‘succeed’.