Post war Iran was ruled by Mohammad Reza Shah. He was supported by the West and he focused on secularisation and modernisation. However, his autocratic rule and the unpopularity of his policies led to a an Islamic revolution in 1979 and his replacement by the Grand Ayatollah Ruhollah Khomeini. This revolution shocked the world and led to a realignment of global alliances. It also led directly to the Iraq-Iran War.