The Iranian Revolution, also known as the Islamic Revolution, was a series of events that culminated in the overthrow of the Pahlavi dynasty in 1979. The revolution also led to the replacement of the Imperial State of Iran by the present-day Islamic Republic of Iran, as the monarchical government of Mohammad Reza Pahlavi was superseded by the theocratic government of Ayatollah Ruhollah Khomeini, a religious cleric who had headed one of the rebel factions. The ousting of Pahlavi, the last Shah of Iran, formally marked the end of Iran's historical monarchy.