Ali ibn Abi Talib (AS), nicknamed Amir al-Mu'minin, is the first Imam of the Shiites, the cousin and son-in-law of the Prophet Muhammad (PBUH), the husband of Hazrat Zahra (AS), and the father of Imam Hassan and Imam Hussein (AS). He was the first man to believe in the Prophet of Islam and was specifically given the title Amir al-Mu'minin by the Prophet. The Prophet appointed Hazrat Ali as his successor at Ghadir Khum by God's command and took the oath of allegiance from the people. However, after the Prophet's death in the year 11 AH, some of the Muhajirin and Ansar disobeyed this order and arbitrarily swore allegiance to Abu Bakr as the caliph of the Muslims in the Saqifa of Bani Sa'ida! This event led to the fact that the Prophet effectively became the caliph in the year 35 AH, after Uthman. His reign was generally marked by conflict with Muawiyah, the followers of Jamal, and the Khawarij, and he was finally martyred in 40 AH at the age of 63 by a Khawarij named Ibn Muljam Muradi. The issue of the caliphate of Imam Ali (a.s.) is an issue that divides Muslims into two groups: Shiites and Sunnis; Shiites consider him the immediate successor of the Prophet (pbuh) and Sunnis consider him the fourth caliph.