Ali himself was firmly convinced of his legitimacy for caliphate based on his close kinship with Muhammad, his intimate association and his knowledge of Islam and his merits in serving its cause. He told Abu Bakr that his delay in pledging allegiance (bay'ah) as caliph was based on his belief of his own prior title. Ali did not change his mind when he finally pledged allegiance to Abu Bakr and then to Umar and to Uthman but had done so for the sake of the unity of Islam, at a time when it was clear that the Muslims had turned away from him.[1][41]