Caliphate: the rulership of ISLAM. Since Islam is theoretically a theocracy, the caliph is ideally both temporal and spiritual leader of the Muslims. When Mohammad the Prophet died, Abu Bakr was chosen as the first caliph. After the caliphate of Ali (656-61) the caliphate split between the Umayyads, who ruled from Damascus, and the Abbasids, who ruled from Baghdad. The Abbasids massacred the Umayyads in 750, but one member escaped to Spain, where he established the Western Caliphate, or the Caliphate of Córdoba; it lasted until 1031. A third caliphate, established by the Fatimid sect in Africa, lasted from 909 to 1171. After the rise of the Ottoman Turks, the sultans assumed the title of caliph. The title died out with the last sultan in 1924.