The Aga Khan, known for his triumphs in horse racing, dazzling wealth and development work around the world, has died in Lisbon at the age of 88, according to the Aga Khan Development Network on X.

The announcement of his designated successor will follow, the network said.

The 49th hereditary imam or spiritual leader of the world’s 15 million Ismaili Muslims, his name also became synonymous with success as a racehorse owner, with the thoroughbred Shergar among his most famous, Reuters reported.

The multi-millionaire, perhaps billionaire, also enjoyed a lavish lifestyle, characterised by private jets, a $200 million super-yacht and a private island in the Bahamas.

Estimates of his wealth varied from $800 million to $13 billion, with his money coming from his family inheritance, his horse breeding business and his personal investments in tourism and real estate.

The international jet setter – who held British, French, Swiss and Portuguese citizenship – also poured millions into helping people in the poorest parts of the world, read the report.

“If you travel the developing world, you see poverty is the driver of tragic despair, and there is the possibility that any means out will be taken,” he told the New York Times in a rare interview in 2007.

By assisting the poor through business, he told the newspaper, “We are developing protection against extremism”.

Prince Shah Karim Al Husseini was born on Dec. 13, 1936 in Geneva and spent his early childhood in Nairobi, Kenya.

He later returned to Switzerland, attending the exclusive Le Rosey School before going to the United States to study Islamic history at Harvard.

When his grandfather Sir Sultan Mahomed Shah Aga Khan died in 1957, he became the imam of the Ismaili Muslims, a branch of Shia Islam, at the age of 20.

His grandfather chose Karim as his successor over his flamboyant son – Karim’s father Prince Aly Khan – who was once married to Hollywood actress Rita Hayworth, Reuters reported.

As Aga Khan — derived from Turkish and Persian words to mean commanding chief — he was believed by Ismailis to be a direct descendant of the Prophet Mohammad through the prophet’s cousin and son-in-law, Ali, the first Imam, and his wife Fatima, the Prophet’s daughter.

He was the fourth holder of the title which was originally granted in the 1830s by the emperor of Persia to Karim’s great-great-grandfather when the latter married the emperor’s daughter.

The role included providing divine guidance for the Ismaili community, whose members live in Central Asia, the Middle East, South Asia, sub-Saharan Africa, Europe and North America.

After his father died in May 1960, the Aga Khan initially pondered whether to continue his family’s long tradition of thoroughbred racing and breeding.

But after winning the French owners’ championship in his first season he was hooked.

“I have come to love it,” he said in a 2013 interview with Vanity Fair. “It’s so exciting, a constant challenge. Every time you sit down and breed you are playing a game of chess with nature.”

His stables and riders, wearing his emerald-green silk livery, enjoyed great successes with horses like Sea the Stars, which won the Epsom Derby and the 2,000 Guineas; and Sinndar, which also won the Epsom Derby, the Irish Derby and the Prix de l’Arc de Triomphe in the same year, 2000.

But perhaps his most famous horse was Shergar, which won the Epsom Derby, the Irish Derby and the King George, before being kidnapped in February 1983 from Ireland’s Ballymany stud farm.

A ransom demand was made, with the mafia, former Libyan leader Muammar Gaddafi and the IRA all suggested as suspects. No money was paid, and no trace of the horse was ever found.

The Aga Khan set up the Aga Khan Development Network in 1967. The group of international development agencies employs 80,000 people helping to build schools and hospitals and providing electricity for millions of people in the poorest parts of Africa and Asia, read the report.

He mixed his development work with private business, owning for example in Uganda a pharmaceutical company, a bank and a fishnet factory.

“Few persons bridge so many divides — between the spiritual and the material; East and West; Muslim and Christian — as gracefully as he does,” Vanity Fair wrote in its 2013 article.

He was married twice, first in 1969 to former British model Sarah Croker Poole, with whom he had a daughter and two sons. The couple divorced in 1995.

In 1998 he married German-born Gabriele zu Leiningen, with whom he had a son. The couple divorced in 2014.