PARIS, 5 FEB

Aga Khan, who became the spiritual leader of Ismaili Muslims at age 20 as a Harvard undergraduate and poured a material empire built on billions of dollars in tithes into building homes, hospitals and schools in developing countries, died on Tuesday at the age of 88.

His Aga Khan Development Network and the Ismaili religious community announced that His Highness Prince Karim Al-Hussaini, the Aga Khan IV and 49th hereditary imam of the Shia Ismaili Muslims, died in Portugal surrounded by his family.

His successor was designated in his will, which will be read in the presence of his family and religious leaders in Lisbon before revealing the name. The successor is chosen from among his male progeny or other relatives, according to the Ismaili community's website.

Considered by his followers to be a direct descendant of the Prophet Muhammad, His Highness Prince Karim Aga Khan IV was a student when his grandfather passed over his playboy father as his successor to lead the diaspora of Shia Ismaili Muslims, saying his followers should be led by a young man “who has been brought up in the midst of the new age.”

Over decades, the Aga Khan evolved into a business magnate and a philanthropist, moving between the spiritual and the worldly with ease.

While his death was announced late in the day in Europe and the Middle East, ceremonies were already being held Tuesday in Ismaili communities in the US. Condolences poured in online from charity groups he supported, as well as the equestrian world, where he was a well-known figure.