Ayatollah Ali Khamenei is Iran's Supreme Leader, a position he has held since 1989. Ayatollah Khamenei is the most powerful man in Iran, though one of the country's least scrutinised politicians. So who is this man? And how has he consolidated the Revolution? The BBC's Iran correspondent, James Reynolds, charts the Ayatollah’s reign and, through a number of interviews with relatives, biographers and politicians, builds a profile of Iran's most powerful man.