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 ...

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 ...

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, on Sept. 18, 2013. | Manish Swarup/AP ...

The Aga Khan, who became the spiritual leader of the world’s millions of Ismaili Muslims at age 20 and then evolved into a business magnate and philanthropist, died Tuesday.