Aga Khan (chief commander) is the title of the imam, or spiritual leader, of the sect of Moslems known as Nizari Ismailis. The title was granted in 1818 by the Shah of Persia.

The Ismailis are Shias, one of the two great sects of Islam. Unlike the Sunnis, the major group, the Shias believe that the imam must be a descendant of the prophet Mohammed through Hasan and Husain, the sons of his daughter Fatima. The Ismailis, who trace their origin to the 8th century, were formed around the followers of Ismail, a descendant of Husain. One branch, the Nizari Ismailis, established itself in Persia in a number of strong fortresses in the 11th century.

Aga Khan I

Hasan Ali Shah (1800-1881) had the title Aga Khan bestowed on him for his services to Fath Ali, the Persian ruler, whose daughter he married. The Aga Khans thus have the...