The Iranian Revolution was the Shia Islamic revolution that replaced the secular monarchy of Shah Mohammad Reza Pahlavi with a theocracy led by Ayatollah Ruhollah Khomeini. Its causes continue to be the subject of historical debate and are believed to have stemmed partly from a conservative backlash opposing the westernization, modernization and secularization efforts of the Western-backed Shah, as well as from a more popular reaction to social injustice and other shortcomings of the ancien régime.
