In 1979, Iran's Shah Mohammad Reza Pahlavi was overthrown by the Islamic Revolution, giving way to an Islamic republic led by the Ayatollah Khomeini. The influence of revolutionary Shi'ite Islam grew in the region, particularly in countries with large Shi'ite populations, especially Iraq. Saddam was afraid that radical Islamic ideas were quickly spreading inside his country among most of the Shi'ite people. He worried that these ideas would go against his leadership.