Ali was the cousin and son-in-law of the Islamic prophet Muhammad, and a member of the Ahl al-Bayt.[3] According to Shias, Ali was the first Imam who is believed to be the rightful successor to Muhammad, divinely appointed successors of Muhammad who are claimed by the Shias.[4] Although Ali was regarded, during the lifetime of Muhammad, as his initial successor, it would be 25 years before he was recognized with the title of Caliph (successor).