LISBON, Portugal — Rahim Al-Hussaini was named Wednesday as the new Aga Khan, spiritual leader of the world’s millions of Ismaili Muslims.

He was designated as the Aga Khan V, the 50th hereditary imam of the Shiite Ismaili Muslims, in his father’s will. His father died Tuesday in Portugal.

The Aga Khan is considered by his followers to be a direct descendant of the Prophet Muhammad and is treated as a head of state.