Rahim Al-Hussaini was named Wednesday as the new Aga Khan, spiritual leader of the world’s millions of Ismaili Muslims, following the death of his father.

The Aga Khan was given the title of “His Highness” by Queen Elizabeth in July 1957, two weeks after his grandfather the Aga Khan III unexpectedly made him heir to the family’s 1,300-year dynasty as leader of the Ismaili Muslim sect.

The Aga Khan IV, the spiritual leader of the world’s Shi’ite Ismaili Muslims, has died at the age of 88. The wealthy imam, who promoted a moderate form of Islam, has also been known for his multimillion-dollar development projects that have benefited communities throughout Asia and Africa.