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.

Prince Karim, 88, 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.

Prince Rahim Al-Hussaini has succeeded his father to become the 50th hereditary Imam, or spiritual leader, of Ismaili Muslims. He was named after the will of his late father Prince Karim Aga Khan

A burial service for Aga Khan IV, the 49th hereditary imam of the Shiite Ismaili Muslims, was held in the southern Egyptian province of Aswan on Sunday. After a procession through the streets, his body was carried down the Nile in a white boat.

Canadian Prime Minister Justin Trudeau and Spain’s King Emeritus Juan Carlos were among the dignitaries who attended Saturday’s private ceremony for His Highness Prince Karim Al-Hussaini at the Ismaili community center. Portugal’s President Marcelo Rebelo de Sousa and the mayor of Lisbon were also among the mourners.

Prince Karim, Aga Khan IV, was laid to rest in a private ceremony in Aswan, Egypt. His son, Rahim Al-Hussaini, has been named Aga Khan V, continuing the Ismaili Muslim spiritual leadership. World leaders attended a service in Lisbon.