The years leading up to the autumn of 1979 in Iran proved to be turbulent, resulting in a radical transformation of the nation. The U.S had backed the semi-absolutist monarchy of Mohammad Reza Shah Pahlavi, even when the increasing popularity of Islamic fundamentalism, Iranian Nationalism, and opposition to western influence exploded, culminating in protests against the Shah in 1977. The Shah used increasingly brutal tactics to suppress rebellion; his actions only further inflamed the revolutionary fervor of the populace.
Organized armed resistance began in 1977. The Shah fled the country on January 16, 1979, leaving a provisional government in power. Meanwhile, the fundamentalist leader Ruhollah Khomeini, who had lead opposition movements before his exile, returned and resumed leadership over the revolution. Khomeini rallied his forces and disposed of both residual royalist troops and the provisional government that ruled in the Shah’s name, thus formally establishing himself as Supreme Leader of the new Islamic Republic. Rival factions were subverted, and Revolutionary Guards roamed the country to ensure the preservation of the new order.