Various and intricate causes brought about civil war, and deep hatred followed quickly; after that came the election in Damascus of Muavia, the governor of Syria, as a Kalif to overthrow Aly, whom many Mohammedans would not acknowledge. The father of Muavia had been one of the most bitter enemies of the Prophet. This hatred was shared fully by the son, who left nothing undone to rouse Syria to the utmost against Aly; he even had the blood-stained clothes of Othman exhibited in the principal mosque of Damascus. A fierce but drawn battle at Siffin between these two Kalifs was fruitless; an arbitration as to who should be Kalif settled nothing and pacified no man. Next came the winning of Egypt by Muavia as the first Ommayad Kalif. There were two Kalifs now ruling de facto in Islam, Muavia at Damascus, and Aly at Kufa. In 661 Aly fell by the hand of an assassin. Aly’s son, Hassan, succeeded him, but resigned after six months of rule, and retired to Medina where one of his many wives poisoned him, incited, as partisans of Aly insisted, by Muavia. Muavia was now the sole Kalif of Islam. Election had been attended with peril; there was danger of outbreaks and slaughter. In three cases the chance had been narrow, and the fourth choice had brought bitter warfare. Three elections had been held at Medina, and made by the men of that city; the fifth, that of Hassan, at Kufa. Muavia had been chosen at Damascus. Since Medina was no longer the capital really, it could not choose a Kalif or confirm him. Election must be at the chief place of government, if anywhere. Troubles such as those which had followed the election of Aly might recur in the future and threaten, or even cut short the existence of Islam. The system of election was unsafe in that turbulent society. To avoid these great perils Muavia planned to choose a successor while he himself was still ruling. His own son Yezid was the candidate. If he could win for Yezid an oath of allegiance from most of the Moslems he would secure power for his family and prevent a contested election. After working a time with great industry and keenness Muavia succeeded. Deputations from all the chief cities, also from each province, appeared at Damascus to do the hidden will of Muavia. These deputations all named Yezid as heir of the Kalif and chose him. They gave then an oath of allegiance and homage. Arabian Irak and Syria also joined in this oath.