Answer:
Western interventions
Step-by-step explanation:
The Iranian Revolution (also known as the Islamic Revolution or Revolution of 1979) refers to the process of mobilizations that led to the overthrow of the Pahlavi Dynasty under the sah Mohammad Reza Pahleví in 1979 (who had the support of the United Kingdom and the United States), and that meant the establishment of the Islamic Republic currently in force in Iran. The leader of the revolution was Ayatollah Khomeini, who had support from various leftist and Islamic organizations plus the Iranian student movements while he was in exile.
The demonstrations against the Shah Reza Pahleví began in 1977, and intensified in January 1978 with the union of secular and religious groups in a campaign of civil resistance. Between August and December of the same year, strikes and protests paralyzed the country. Consequently, the shah left Iran, leaving for exile on January 16, 1979 and leaving the power in the hands of a regency council and an opposition prime minister; He was the last Persian monarch. The opposition leader, Ayatollah Khomeini (who was in exile during the reign of Reza Pahlevi), was authorized to return to Iran by the government, and upon his arrival in Tehran he was applauded by a crowd waiting for him. The royal provisional government collapsed on February 11 when it was defeated in the street armed struggle by guerrilla groups and rebel troops that officially took Khomeini to power. Subsequently the Iranians voted in a referendum to become an Islamic republic on April 1, 1979, and approved a republican and theocratic Constitution where Khomeini became "Guide of the Revolution" in December of the same year.
The revolution in short meant the replacement of a pro-Western authoritarian monarchy by a republican, authoritarian and anti-Western theocracy based on the concept of Tutela de los Juristas Islámicos (wilayat faqih).