Second son of Ali b. Abi Talib, Muhammad's cousin, and Fatima, Muhammad's daughter.
Muslim tradition portrays an affectionate relationship between Muhammad and his grandsons. Husayn was still a child when his grandfather died; the remainder of his youth and his young adulthood were spent accompanying his father on his campaigns.
Husayn remained quiescent after the death of his father, although he reproached his brother Hasan for abdicating to Muawiya. He was, however, one of five men who refused to acknowledge Muawiya's son, Yazid, as his successor. After Muawiya's death in 680, Yazid ordered the governor of Medina to force Husayn and Ibn al-Zubayr to pay him allegience. Ibn al-Zubayr fled to Mecca, while Husayn asked for a delay, then went to Mecca with his family two days later.
Several months later, Husayn received invitations from the Shi`ites of Kufa to lead them in a revolt; Husayn prudently sent his cousin Muslim b. Aqil to gather pledges of support beforehand. However, news of Muslim's activity reached Yazid, and he installed a new governor, Ibn Ziyad, who initiated harsh measures to counteract the dissent and frighten Husayn's sympathizers. Muslim himself was found and put to death, but unfortunately not before sending an encouraging report along with thousands of signatures of support. Husayn then set out for Kufa.
Upon hearing of Husayn's departure, Ibn Ziyad sent out his forces to watch Husayn and to persuade him to turn back. Husayn and his small band of supporters were finally halted at Kerbala. After attempts at reaching an agreement failed, Ibn Ziyad's forces attacked; all of Husayn's fighters were killed and Husayn was beheaded.
The battle at Kerbala had serious consequences for the development of the Sunni-Shi`ite split. The Shi`a mourn Husayn as a martyr who had fought against an unjust ruler; he is glorified as the third rightful leader of the Muslim community after Muhammad. In later Muslim tradition, influenced by extremist Shi`ite views, Husayn becomes a legendary figure with whom are associated numerous marvels and miracles.