Aga Khan, in Shīʿite Islam, title of the imams of the Nizārī Ismāʿilī sect. The title was first granted in 1818 to Ḥasan ʿAlī Shah (1800–81) by the shah of Iran. As Aga Khan I, he later revolted against Iran (1838) and, defeated, fled to India. His eldest son, ʿAlī Shah (died 1885), was briefly Aga Khan II. ʿAlī Shah’s son Sultan Sir Moḥammed Shah (1877–1957) became Aga Khan III. He acquired a leading position among India’s Muslims, served as president of the All-India Muslim League, played an important part in the Round Table conferences on Indian constitutional reform (1930–32), and in 1937 was appointed president of the League of Nations. He chose as his successor his grandson Karīm al-Ḥusayn Shah (born 1936), who as Aga Khan IV became a strong community leader, founding the Aga Khan Foundation, an international philanthropic organization, and other agencies offering educational and other services.