The most significant outcome of the Iranian Revolution, which culminated in 1979, was the establishment of the Islamic Republic of Iran. The revolution resulted in the overthrow of the Pahlavi monarchy, led by Mohammad Reza Shah, and the ascent of Ayatollah Khomeini as the Supreme Leader. This regime shift transformed Iran's political landscape by instituting a theocratic government grounded in Islamic law, significantly altering its domestic policies and foreign relations. Furthermore, the revolution inspired various Islamic movements across the Middle East while also marking a shift toward anti-Western sentiment, particularly against the United States.