His Highness Prince Karim Aga Khan IV, is the 49th hereditary Imam of the Shia Imami Ismaili Muslims. He was born on December 13, 1936 in Geneva. He is the son of Prince Aly Khan  and his wife Princess Tajudaulah (Joan Yarde-Buller), daughter of Lord Churston. After spending his early childhood in Nairobi Kenya, he attended Le Rosey school in Switzerland and
graduated from Harvard University with an honors degree in Islamic history in 1959. Aga Khan IV succeeded his grandfather, Sir Sultan Mahomed Shah, to the Imamat on July 11, 1957 at  the age of twenty. 

In 1969, Aga Khan IV married Begum Salimah (English-born Sarah Croker-Poole). They have three children, Princess Zahra born on September 18, 1970, Prince Rahim born on October  12, 1971 and Prince Hussain born on April 10, 1974. In 1995 Agakhan IV and Begum Salimah divorced ending their 25-year marriage.

In May 30,1998 AgaKhan IV married Begum Inaara (German-born Princess Dr. Gabriele zu Leiningen). It was the second marriage for both. She has a six-year-old daughter Theresa from  her first marriage. Aga Khan IV became the father of another son Prince Aly Muhammad Khan onMarch 7, 2000 in Paris, France by Begum Inaara.

Under the Aga Khan's leadership, many of the Aga Khan Network's principal institutions have been established and each has a specific mandate to improve the quality of life for people of all  faiths or origins.