When his grandfather Sir Sultan Mahomed Shah Aga Khan died in 1957, he became the imam of the Ismaili Muslims, a branch of Shia Islam, at the age of 20.

PARIS — The Aga Khan, who became the spiritual leader of the world's millions of Ismaili Muslims at age 20 as a Harvard undergraduate and poured a material empire built on billions of dollars in ...

The Aga Khan, spiritual head of Ismaili Muslims, listens to a speech during the inauguration of the Aga Khan Academy in Hyderabad, India, Friday, Sept. 20, 2013. Credit: AP/Mahesh Kumar A.

The Aga Khan, who became the spiritual leader of the world’s millions of Ismaili Muslims at age 20 as a Harvard undergraduate and poured a material empire built on billions of dollars in tithes ...

PARIS – The Aga Khan, who became the spiritual leader of the world’s millions of Ismaili Muslims at age 20 as a Harvard undergraduate and poured a material empire built on billions of dollars ...

The Aga Khan, spiritual head of Ismaili Muslims, listens to a speech during the inauguration of the Aga Khan Academy in Hyderabad, India, Friday, Sept. 20, 2013. (AP Photo/Mahesh Kumar A., File) ...

FILE – The Aga Khan, spiritual head of Ismaili Muslims, listens to a speech during the inauguration of the restored 16th century Humayun’s Tomb in New Delhi, India, Sept. 18, 2013.