Abu al-Hasan Ali ibn Abi Talib al-Hashimi al-Qurashi (13 Rajab 23 AH/17 March 599 CE – 21 Ramadan 40 AH/27 January 661 CE) was the cousin and son-in-law of the Prophet Muhammad, a member of his household, and one of his companions. He is the fourth of the Rightly-Guided Caliphs according to the Sunnis, one of the Ten Promised Paradise, and the first Imam according to the Shia.
He was born in Mecca, and some historical sources indicate that he was born inside the Kaaba. His mother was Fatima bint Asad al-Hashimiyya. He converted to Islam before the Prophet’s migration, and he was the second or third person to convert to Islam, and the first boy to convert to Islam. He migrated to Medina three days after the Prophet’s migration. The Prophet Muhammad made him his brother when he established brotherhood among the Muslims, and he married him to his daughter Fatima in the second year of the Hijra.
Ali participated in all of the Prophet’s battles except the Battle of Tabuk, where the Prophet Muhammad left him in charge of Medina. He was known for his strength and prowess in combat, and was a key factor in the Muslims’ victory in various battles, most notably the Battle of the Trench and the Battle of Khaybar. Ali was trusted by the Prophet Muhammad, and was one of his scribes and most important ambassadors and ministers.