The Iranian Revolution began in 1978 as demonstrations against the oppressive rule of Shah Mohammad Reza Pahlavi and to overthrow the monarchy. By 1979, the revolution had succeeded in removing the Shah from power and establishing Ayatollah Ruhollah Khomeini as the new leader of Iran. Khomeini established an Islamic republic and new constitution that reflected the traditional Islamic values of the population that the Shah had suppressed. The revolution transformed Iran from a Western-allied monarchy to an Islamic republic and had significant geopolitical impacts.