Background, Titles, Styles and Honors of His Highness Aga Khan
Prince Shah Karim Al Hussaini, Aga Khan IV, KBE, CC is the 49th and current Imam of Nizari Ismailism, a denomination of Isma’ilism within Shia Islam with an estimated 10–15 million adherents (10–12% of the world’s Shia Muslim population).The Aga Khan is a business magnate with British and Portuguese citizenship, as well as a racehorse owner and breeder. He has held this position of Imam, under the title of Aga Khan IV, since 11 July 1957, when, at the age of 20, he succeeded his grandfather, Sir Sultan Muhammad Shah Aga Khan III. It is believed that the Aga Khan is a direct lineal descendant of the Islamic prophet Muhammad through Muhammad’s cousin and son-in-law, Ali, considered the first Imam in Shia Islam, and Ali’s wife Fatima az-Zahra, Muhammad’s daughter from his first marriage.
Read more at Wikipedia (https://en.wikipedia.org/wiki/Aga_Khan_IV)