Prince Karim, Aga Khan IV, NPk, NI, KBE, CC, GCC, GCIH, GCM (Arabic: سمو الأمیر شاہ کریم الحسیني آقا خان الرابع‎; born December 13, 1936; Aga Khan is also transliterated Aqa Khan and Agha Khan) is a Swiss-born French businessman, racehorse owner and breeder, and the 49th and current Imam of Nizari Ismailism — a minority denomination of Shia Islam with 5-15 million adherents (under 10% of the Shia population). He has held the position of Imam under the title of Aga Khan IV since July 11, 1957, when, at the age of 20, he succeeded his grandfather, Sultan Muhammad Shah Aga Khan, also known as Aga Khan III. The Aga Khans claim to be direct descendants of the Prophet Muhammad through his cousin and son-in-law, Ali, considered the first Imam in Shia Islam, and his wife Fatima az-Zahra, the Prophet’s daughter from his first marriage. As the Imam of Nizari Ismailism, the Aga Khan IV is considered by his followers to be the proof or hujjah of God on earth as well as infallible and immune from sin (just as an Imam is viewed in most other denominations of Shia Islam). He is further considered by his followers to be the carrier of the eternal Noor of Allah ("Light of God" - a concept unique to certain denominations of Shia Islam). In 1986, the Aga Khan ordained the current Ismailia Constitution - an ecclesiastical decree affirming to Nizari Ismailis his "sole right to interpret the Quran and provide authoritative guidance on [all] matters of faith" and formalizing his sole discretion, power and authority for the governance of Nizari Ismaili jamats (places of worship) and institutions.