Sayyid Ruhollah Mūsavi Khomeini, known in the Western world as Ayatollah Khomeini, was an Iranian Shia Islam religious leader and politician. He was the founder of Iran as an Islamic republic and the leader of its 1979 Iranian Revolution that saw the overthrow of the last Shah of Iran, Mohammad Reza Pahlavi, and the end of 2,500 years of Persian monarchy. Following the revolution, Khomeini became the country's Supreme Leader, a position created in the constitution of the Islamic Republic as the highest-ranking political and religious authority of the nation, which he held until his death. He was succeeded by Ali Khamenei on 4 June 1989.