The country was a battleground for competing foreign powers, particularly Britain and Russia, who sought to control its vast oil reserves. This period of foreign interference and exploitation sowed the seeds of anti-imperialist sentiment among the Iranian people, who increasingly demanded more control over their own resources and government. In 1953, a CIA-backed coup overthrew the democratically elected Prime Minister Mohammad Mossadegh, who had nationalized Iran's oil industry. The coup installed Mohammad Reza Pahlavi, known as the Shah, as the country's absolute ruler. The Shah embarked on a modernization program that sought to westernize Iran's economy and society, but his reforms were seen as repressive and alienating to many Iranians, particularly traditionalists and religious conservatives.