Hasan ibn Ali

Hasan ibn Ali, also called al-Mujtaba ("the chosen") and Abu Muhammad, was the elder son of Ali ibn Abi Talib and Fatima, the Prophet Muhammad's daughter, making him the Prophet's grandson. Sources place his birth in Medina around 3 AH; the date is most often given as 15 Ramadan 3 AH (c. 625 CE), though some sources give 624 and early dates are traditional estimates that vary. He grew up in Medina; reports of his childhood in the Prophet's household belong largely to later tradition (sira and manaqib, devotional life-accounts) rather than firmly attested record.

After his father Ali was assassinated in early 661, supporters in Kufa (in present-day Iraq) acclaimed Hasan as caliph. His rule lasted only about seven months. As he moved against Mu'awiya ibn Abi Sufyan, the governor of Syria and rival claimant, Hasan's camp at al-Mada'in (the early-Islamic town at the site of former Ctesiphon) fractured: he was wounded in a mutiny, and amid defections he negotiated terms and ceded authority to Mu'awiya in August 661. The exact terms are recorded differently in the sources.

He then withdrew to Medina, living away from politics until his death, traditionally dated c. 50 AH (most often given as 2 April 670 CE, with variants of 48, 49, 58 and 59 AH in the sources). Many early sources report he was poisoned, naming his wife Ja'da bint al-Ash'ath and implicating Mu'awiya; some scholars (e.g., Veccia Vaglieri) note illness cannot be ruled out. He was buried at the al-Baqi cemetery. Shia tradition (Twelver and Ismaili) honors him as the second Imam, divinely designated; this is a position held by those communities, not a matter settled across Islam.