(d. ca. 713)
Fourth Shii imam, great-grandson of Muhammad, and the only son of Husayn who survived the massacre of Shiis at Karbala. Was protected by Husayn's sister, Zaynab, who convinced Yazid's troops not to kill him, leaving an heir to the imamate. Became a noted scholar in Hejaz and devoted himself to prayer. Quiescent in attitude toward the Umayyad dynasty, leading many Shiis to abandon him in favor of Ali's third son by a Hanafi woman, marking a break in the prior belief that only descendants of Ali and Fatimah could serve as imams. Reinterpreted in the twentieth century as an example of patience and perseverance when numerical odds are against the Shii community.