Cleric who led the institution that chooses Iran's Supreme Leader. Cleric who headed Iran's most influential body charged with choosing or dismissing the nation's Supreme Leader, Ayatollah Mohammadreza Mahdavi Kani was the chairman of the Assembly of Experts - a body of 86 senior clerics that monitor the Supreme Leader and picks a successor after his death. The Assembly of Experts has only once picked a supreme leader since 1979 Islamic Revolution - in 1989, when it chose Ayatollah Ali Khamenei to succeed his late mentor, Ayatollah Khomeini. Ayatollah Kani had been chairman of the Assembly since 2011. A moderate conservative Ayatollah Kani also served as acting prime minister and interior minister in the 1980s. Born in the village of Kan, near Tehran, the son of an Ayatollah, Mohammadreza Mahdavi studied in a seminary in Qom after 1947. His teachers included Ayatollah Ruhollah Khomeini, leader of the Islamic Revolution. He became an opponent of the Shah's regime at 18 and in early 1960s he continued his fight against the brutal regime. Before revolution Ayatollah Kani formed part of the Revolutionary Council and later took up various positions.