The Aga Khan, imam of the Ismaili Muslims, has died "peacefully" at the age of 88 in Lisbon, his foundation announced on Tuesday.

"His Highness Prince Karim Al-Hussaini, Aga Khan IV, 49th hereditary Imam of the Shia Ismaili Muslims and direct descendant of the Prophet Muhammad (peace be upon him), passed away peacefully in Lisbon on 4 February 2025, aged 88, surrounded by his family," the Aga Khan Foundation posted on social media.

"The announcement of his designated successor will follow," it added in relation to who could become the fifth person to hold the post since the 19th century. 

Who was the Aga Khan?

Considered by those that followed him to be a direct descendant of the Prophet Muhammad, the Aga Khan became the spiritual leader of the Ismaili Muslims at the age of 20 as a Harvard undergraduate. He poured a material empire built on billions of dollars in tithes into constructing homes, hospitals and schools in developing countries.

Present most notably in central and southern Asia, Africa and the Middle East, the Ismaili community numbers some 12 to 15 million people, according to its website. It is a branch of Shiite Islam.

The Aga Khan also held British and Portuguese citizenship and the Ismaili leadership is based in Lisbon, the Portuguese capital, where there is also a significant community.

Despite his role as the spiritual head of the Ismaili Muslims, he was reluctant to talk about Middle East conflicts, religious fundamentalism or Sunni-Shiite tensions.

UN chief 'saddened' by death

United Nations Secretary-General Antonio Guterres has paid tribute to the spiritual leader.

He said he was "deeply saddened" at the news, describing the Aga Khan as "a symbol of peace, tolerance and compassion in our troubled world."

Nobel Peace laureate and education campaigner Malala Yousafzai said the Aga Khan's legacy will "live on through the incredible work he led for education, health and development around the world."

Edited by: Saim Dušan Inayatullah