The spiritual leader of the Ismaili Muslims, Prince Karim Aga Khan IV, passed away peacefully at the age of 88 at his home in Lisbon surrounded by family, it was announced by the Ismaili religious community late on February 4.

His Aga Khan Development Network, or AKDN, has been active in Central Asia—most particularly in Tajikistan’s Gorno-Badakhshan Autonomous Region, or GBAO, home to the oppressed Pamiri mountain peoples—since the 1990s.

In November, Central Asia specialist Bruce Pannier reported for bne IntelliNews on how the 49th hereditary imam of the Ismaili community has served as the chief beneficiary to the Pamiri—but in a grievous blow to the minority, was being cut off from further cooperation by Tajikistan’s Rahmon regime.

The Switzerland-born Aga Khan, a billionaire, who by the Ismaili is considered a direct descendant of the prophet Muhammad, and AKDN have supported educational, healthcare and economic projects, among others, in Tajikistan and worldwide.

Amid accusations of Pamiri separatism, authorities in Tajikistan have nationalised AKDN properties in GBAO and frozen activities of an educational institution built by the Aga Khan in the region.

The AKDN works in more than 30 countries, but was unable to have a presence in Tajikistan during the time of the Soviet Union and only managed to start operations there in 1995, four years after the collapse of the USSR. Since then, over nearly 30 years, it has invested more than $1bn in Tajikistan.

Ismailism is a branch of Shia Islam. The community with the highest percentage of Ismailis is the Pamiri of GBAO but Ismailis can be found across Central Asia and in countries including Afghanistan, India, Pakistan, Bangladesh, Tanzania, Kenya, Syria, Iran and Jordan.

An announcement on the Aga Khan’s successor is to follow.

Treated as a head of state, the Aga Khan was given the title of “His Highness” by the UK’s Queen Elizabeth II in July 1957, two weeks after his ailing grandfather, the Aga Khan III, in an unexpected move, made him heir to the family’s 1,300-year dynasty as leader of the Ismaili Muslim sect. He had departed Harvard to be at his grandfather’s side. Eighteen months later, he returned to the US with an entourage.

“I was an undergraduate who knew what his work for the rest of his life was going to be,” he said in a 2012 interview with Vanity Fair. “I don’t think anyone in my situation would have been prepared.”

He also told the magazine: “We have no notion of the accumulation of wealth being evil.

“The Islamic ethic is that if God has given you the capacity or good fortune to be a privileged individual in society, you have a moral responsibility to society.”

The Aga Khan is survived by three sons and a daughter.