Hasan ibn Ali

Hasan ibn Ali (Arabic: حسن ابن علي, romanized: Ḥasan ibn ʿAlī; c. 625 – 2 April 670) was the eldest son of Ali and Fatima, the elder brother of Husayn, and the eldest grandson of the Islamic prophet Muhammad. He briefly ruled as caliph from January to August 661 and is the second Imam in Shia Islam, succeeding his father Ali and preceding his brother Husayn. Hasan is a prominent member of the Ahl al-Bayt and the Ahl al-Kisa, and a participant in the Event of the Mubahala. Muhammad described Hasan and Husayn as the leaders of the youth of paradise. Hasan is traditionally described as having had the closest resemblance to the Prophet Muhammad.

Following Ali's assassination, Hasan was acknowledged as caliph in Kufa. His authority was not recognized by Mu'awiya, the governor of Syria and his rival for the caliphate, who led an army toward Kufa while pressuring Hasan to abdicate through a series of letters. In response, Hasan dispatched an advance force under Ubayd Allah ibn al-Abbas to delay Mu'awiya's advance until he could arrive with the main army. Meanwhile, Hasan was severely wounded in an attempted assassination by al-Jarrah ibn Sinan, a member of the Kharijites, a faction opposed to both Ali and Mu'awiya. The attack further demoralized Hasan's army and contributed to widespread desertion. Ubayd Allah and many of his troops subsequently defected after Mu'awiya bribed him.

In August 661, Hasan signed a peace treaty with Mu'awiya. Under the treaty, Hasan ceded the caliphate to Mu'awiya on the condition that the latter should rule in compliance with the Quran and the Sunnah, a council should appoint his successor (rather than appointing one himself), and Hasan's supporters would receive amnesty. Hasan retired from politics and abdicated in Medina, where he died from mercury poisoning in 670. Ja'da bint al-Ash'ath, one of Hasan's wives, is traditionally accused of poisoning him. Reports say that Mu'awiya persuaded her to do so by promising her gold and marriage to his son Yazid. Throughout his reign, Mu'awiya violated the treaty by prosecuting notable supporters of Hasan, and by appointing his son Yazid as his successor, making the caliphate hereditary.

Critics of Hasan have interpreted his treaty with Mu'awiya as evidence of political weakness. His supporters, however, argue that his abdication became necessary due to Mu'awiya's military superiority, the mutiny and fragmentation of Hasan's forces, and his desire to prevent further bloodshed and preserve Muslim unity. Some early Sunni scholars may have considered Hasan's brief rule as rightly-guided (rāshid). In Shia theology, Hasan's course of action is understood in light of his divinely granted infallibility (Iṣmah) and his status as the second Imam. As the rightful successor of Muhammad in Shia Islam, Hasan's comprehensive temporal and religious authority derived from divinely-inspired designation (nass), which was not annulled by abdication to Mu'awiya, who usurped only the temporal authority. Hasan is buried in the Baqi Cemetery in Medina. The shrine that stood over his grave was demolished, along with the cemetery itself, by Wahhabis in 1806 and again in 1925.