View of the courtyard of the Umayyad Mosque, Damascus (706-715) • ISTOCKPHOTO The succession of Mahomet is regulated on the tribal mode by a consensus between the allied clans. Abu Bakr, the first successor (632-634) already very old, is close to Muhammad. He maintains intertribal unity and continues the expansion towards central Arabia. The exit from Arabia initiated under the second successor, Omar (634-644), took place in the classic form of tribal raids. The successes obtained in the west on the Palestinian-Syrian and then Egyptian fronts led to the withdrawal of the Byzantines to the Anatolian plateau. Those obtained on the fronts of Euphratic Iraq, then of Iran, produced the collapse of the empire of the Sassanid Persians. Birth of an empire Under the third successor, Othman, problems began to arise over the sharing of power over the conquered lands, which now had the dimension of an empire. Othman ended up assassinated by disgruntled tribal settlers in 656. Ali, cousin and son-in-law of Muhammad (he was the husband of his daughter Fatima), succeeded him in catastrophic conditions, because the assassins were among his supporters and the relatives of Othman demands revenge. However, it is the powerful Meccan clan, whose leader is Moawiya, governor of Syria. At the end of an indecisive battle, the rivals agree, according to tribal custom, to resort to arbitration which establishes Ali's responsibility after a few months of negotiations. Moawiya is immediately proclaimed caliph by his troops. This is the beginning of the Umayyad caliphate-empire (661-750). Ali ended up assassinated the same year by his former supporters, called the kharidjites (the "outgoing"). On the other hand, neither Shiism nor Sunnism date from this first period. Shiism was born from the rupture of the descendants of Ali with their Abbasid cousins, who had seized power in the name of the revenge of Husayn, son of Ali and grandson of Muhammad, killed in 680 by the Umayyad governor of Iraq. . Sunnism, a movement largely stemming from converted societies in search of a link with the prophetic past, dates from the end of the 9 th century.
