The institution of the Khalifate had hardly been agreed upon when the question of who should occupy it became the subject of violent dissension. The first four khalîfs, whose reigns occupied the first thirty years after Mohammed's death, were Qoraishites, tribesmen of the Prophet, and moreover men who had been his intimate friends. The sacred tradition relates a saying of Mohammed: "The _imâms_ are from Qoraish," intended to confine the Khalifate to men from that tribe. History, however, shows that this edict was forged to give the stamp of legality to the results of a long political struggle. For at Mohammed's death the Medinese began fiercely contesting the claims of the Qoraishites; and during the reign of Alî, the fourth Khalîf, the Khârijites rebelled, demanding, as democratic rigorists, the free election of khalîfs without restriction to the tribe of Qoraish or to any other descent. Their standard of requirements contained only religious and moral qualities; and they claimed for the community the continual control of the chosen leader's behaviour and the right of deposing him as soon as they found him failing in the fulfilment of his duties. Their anarchistic revolutions, which during more than a century occasionally gave much trouble to the Khalifate, caused Islâm to accentuate the aristocratic character of its monarchy. They were overcome and reduced to a sect, the survivors of which still exist in South-Eastern Arabia, in Zanzibar, and in Northern Africa; however, the actual life of these communities resembles that of their spiritual forefathers to a very remote degree. Another democratic doctrine, still more radical than that of the Khârijites, makes even non-Arabs eligible for the Khalifate. It must have had a considerable number of adherents, for the tradition which makes the Prophet responsible for it is to be found in the canonic collections. Later generations, however, rendered it harmless by exegesis; they maintained that in this text "commander" meant only subordinate chiefs, and not "the Commander of the Faithful." It became a dogma in the orthodox Mohammedan world, respected up to the sixteenth century, that only members of the tribe of Qoraish could take the place of the Messenger of God.