Alī ibn Abī Ṭālib was the cousin and son-in-law of the Islamic prophet Muhammad, and ruled over the Islamic Caliphate from 656 to 661. Sunni Muslims consider Ali the fourth and final of the Rashidun (rightly guided Caliphs), while Shi'a Muslims regard Ali as the first Imam and consider him and his descendants the rightful successors to Muhammad, all of which are members of the Ahl al-Bayt, the household of Muhammad. This disagreement split the Ummah (Muslim community) into the Sunni and Shi'a branches.

Muslim sources, especially Shi'a ones, state that during Muhammad's time, Ali was the only person born in the Kaaba sanctuary in Mecca, the holiest place in Islam. His father was Abu Talib ibn Abd al-Muttalib and his mother was Fatima bint Asad, but he was raised in the household of Muhammad, who himself was raised by Abu Talib, Muhammad's uncle. When Muhammad reported receiving a divine revelation, Ali was the first male to accept his message, dedicating his life to the cause of Islam.

Ali migrated to Medina shortly after Muhammad did. Once there Muhammad told Ali that God had ordered Muhammad to give his daughter, Fatimah, to Ali in marriage. For the ten years that Muhammad led the community in Medina, Ali was extremely active in his service, leading parties of warriors on battles, and carrying messages and orders. Ali took part in the early raids against caravans from Mecca and later in almost all the battles fought by the nascent Muslim community.

Ali was appointed Caliph by the Companions of Muhammad (the Sahaba) in Medina after the assassination of the third caliph, Uthman ibn Affan. He encountered defiance and civil war during his reign. In 661, Ali was attacked one morning while worshipping in the mosque of Kufa, and died a few days later. In Muslim culture, Ali is respected for his courage, knowledge, belief, honesty, unbending devotion to Islam, deep loyalty to Muhammad, equal treatment of all Muslims and generosity in forgiving his defeated enemies, and therefore is central to mystical traditions in Islam such as Sufism. Ali retains his stature as an authority on Qur'anic exegesis, Islamic jurisprudence and religious thought. Ali holds a high position in almost all Sufi orders which trace their lineage through him to Muhammad. Ali's influence has been important throughout Islamic history.