Aga Khan IV

Prince Shah Karim al-Hussaini was born prematurely in Geneva, Switzerland, on 13 December 1936, the eldest son of Prince Aly Khan (1911 to 1960) and Joan Yarde-Buller (1908 to 1997), later known as Taj-ud-dawlah Aga Khan, eldest daughter of John Yarde-Buller, 3rd Baron Churston. His brother Prince Amyn was born the following year. Through his mother he had an older half-brother, Patrick Benjamin Guinness (1931 to 1965), from her first marriage to Loel Guinness. His parents divorced in 1949 and his father then married the American actress Rita Hayworth, with whom he had a daughter, Princess Yasmin Aga Khan. Karim spent the Second World War years in Nairobi, Kenya, where he was educated by private tutors.

After Nairobi he spent nine years at Institut Le Rosey in Switzerland, where he said he earned "fair grades". He was admitted to MIT to study science, but his grandfather Aga Khan III vetoed the plan and he went to Harvard University instead, joining the Delphic Club and majoring in Islamic history. He became Imam in 1957 while still an undergraduate, set aside plans for further study, and graduated from Harvard in 1959 with a cum laude Bachelor of Arts in history and a varsity letter for the Harvard men's soccer team. He was also a competitive downhill skier, representing Great Britain at the 1962 FIS Alpine World Ski Championships and Iran at the 1964 Winter Olympics.

Aga Khan III died in July 1957 and his will named his 20 year old grandson as the 49th Imam, bypassing Aly Khan and Sadruddin Aga Khan. It was only the second recorded time in Nizari Ismaili history that a grandson rather than a son was named Imam. Karim was installed on 19 October 1957, with ceremonies in several countries in 1957 and 1958. Queen Elizabeth II granted him the style His Highness in 1957, and the Shah of Iran granted His Royal Highness in 1959, though he preferred His Highness.

In 1972, when Idi Amin expelled people of South Asian origin from Uganda, he contacted Canadian Prime Minister Pierre Trudeau, and Canada took in a large number of Ismaili refugees. He also coordinated resettlement of Ismailis displaced from Tanzania, Kenya and Myanmar. In 1986 he promulgated a written Ismaili Constitution, amended in 1998. His Silver Jubilee (1982 to 1983) launched the Aga Khan University in Karachi, his Golden Jubilee (2007 to 2008) included the founding of the Golden Jubilee Games and the announcement of the Ismaili Center Houston, and his Diamond Jubilee (2017 to 2018) ended with the designation of the Henrique de Mendonca Palace in Lisbon as the Seat of the Ismaili Imamat.

He built the Aga Khan Development Network (AKDN), a family of more than 200 agencies employing roughly 80,000 people, working in health, education, culture, rural development, financial services and enterprise, mainly in Africa, South and Central Asia and the Middle East. Its institutions include the Aga Khan University, the University of Central Asia, the Aga Khan Foundation, the Aga Khan Trust for Culture, the for-profit Aga Khan Fund for Economic Development (whose holdings include Serena Hotels), the Aga Khan Academies and the emergency agency Focus Humanitarian Assistance. He founded the Institute of Ismaili Studies in London in 1977. In a 2006 speech in Germany he explained that the Imamate saw this work not as philanthropy or enterprise separate from faith but as part of the Imam's responsibilities. He was named Global Founding Patron of the Prince's Trust Group in 2019 and AKDN is a founding partner of the Paris Peace Forum.

In 1977 he created the Aga Khan Award for Architecture, a triennial prize totalling US$1 million that recognises buildings serving Muslim societies. In 1979 Harvard and MIT launched the Aga Khan Program for Islamic Architecture with his endowment. Through the Aga Khan Trust for Culture he supported Al-Azhar Park in Cairo, the restoration of the gardens of Humayun's Tomb and Sunder Nursery in Delhi, and Bagh-e Babur in Kabul. In Canada he created the Aga Khan Museum in Toronto, the Delegation of the Ismaili Imamat and the Global Centre for Pluralism in Ottawa.

He ran France's largest racing and breeding operation from his Aiglemont estate at Gouvieux near Chantilly, buying the bloodstock of Anna Dupre in 1977 and Marcel Boussac in 1978. He owned Gilltown Stud in Ireland, the Haras de Bonneval and, from 2005, the Haras d'Ouilly and Haras de Val-Henry, and became majority shareholder of the Arqana auction house in 2006. He was a record winner of the Prix de Diane. His unbeaten filly Zarkava won the 2008 Prix de l'Arc de Triomphe and his colt Harzand won the 2016 Epsom Derby and Irish Derby, while the great Sea the Stars stood at Gilltown. He was the lead owner of Shergar, kidnapped from Ballymany Stud in 1983; the owners refused to pay a ransom and the horse was never recovered. Outside racing he founded Kenya's Nation Media Group (publisher of the Daily Nation) in 1959 and the Yacht Club Costa Smeralda in Sardinia in 1967.

He was known for avoiding parties and gossip columns. On 22 October 1969 (civil) and 28 October 1969 (religious) he married the former British model Sarah Frances Croker Poole in Paris; she became Begum Salimah Aga Khan. They had three children: Princess Zahra (born 18 September 1970), Prince Rahim (born 12 October 1971) and Prince Hussain (born 10 April 1974). The couple lived separately from about 1984 and their divorce was made public in 1994. On 30 May 1998 he married Gabriele Thyssen, formerly married to Prince Karl Emich of Leiningen, at Aiglemont; she became Begum Inaara Aga Khan. Their son Prince Aly Muhammad was born on 7 March 2000. They announced their intention to divorce in 2004, with a settlement reached in French courts in 2011. His main home was Aiglemont in Gouvieux, France.

He spoke constantly about pluralism, tolerance and the gap in understanding between the Muslim world and the West, arguing that the Islamic world was as diverse as the Christian world. He was a Shia signatory of the 2004 Amman Message. After Pope Benedict XVI's 2006 Regensburg lecture he called for dialogue about faith and reason rather than confrontation. He described Canada as the most successful pluralist society in the world. In a 1965 Sunday Times interview he said he had never touched alcohol, explaining that anything that impedes the power of thought is forbidden.

He led the Ismaili community through decolonisation, refugee crises and migration to the West, and left behind a network of universities, hospitals, schools, parks and cultural institutions across some of the poorest regions of the world. In 2014 he became the first faith leader to address a joint session of the Parliament of Canada. After his death, France Galop renamed the Group One Prix d'Ispahan as the Prix Aga Khan IV, and tributes came from UN Secretary-General Antonio Guterres, Justin Trudeau, Emmanuel Macron and many others.

His honours included Knight Commander of the Order of the British Empire (KBE, 2003), Companion of the Order of Canada, honorary Canadian citizenship (2010), Nishan-e-Pakistan (1983), Nishan-i-Imtiaz (1970), Grand Crosses of the Portuguese Orders of Prince Henry (1960), Merit (1998), Christ (2005) and Liberty (2017), the Spanish Order of Civil Merit (1991) and Uganda's Order of the Pearl of Africa (2017). He received the Andrew Carnegie Medal of Philanthropy (2005), the Vincent Scully Prize (2005) and honorary degrees from Harvard (2008), Cambridge (2009), Brown (1996), McGill (1983), Toronto and many other universities.

He died peacefully at his residence in Lisbon, Portugal, on 4 February 2025, aged 88, surrounded by his family, according to the Aga Khan Development Network. The cause of death was not made public. His will, opened in Lisbon on 5 February, named his son Prince Rahim as the 50th Imam, Aga Khan V. A private funeral was held in Lisbon on 8 February 2025, attended by President Marcelo Rebelo de Sousa, Lisbon Mayor Carlos Moedas, Justin Trudeau and former King Juan Carlos I of Spain. On 9 February he was buried in the Mausoleum of Aga Khan in Aswan, Egypt, where his grandfather also lies.