Final answer:
Mohammad Reza Shah Pahlavi led a 25-year dictatorship in Iran, supported by Western interests concerned with oil control, known for its repression and Westernization efforts. The Shah was overthrown in 1979 after widespread protests, leading to the establishment of an Islamic republic with Ayatollah Khomeini emerging as the new leader.
Step-by-step explanation:
Mohammad Reza Shah Pahlavi's rule in Iran, which lasted until 1979, was characterized by a form of modern absolutism under the cover of a constitutional monarchy. His autocratic style of governance, supported actively by US and UK interests primarily for the control of Iranian oil, manifested in a 25-year dictatorship. The Shah's rule was marked by a strong push for Westernization and modernization, the building of a formidable army and secret police called SAVAK, and policies in line with foreign, especially Western, interests.
In response to national discontent and the prime minister's move to nationalize Iran's oil fields, the CIA and MI-6 led Operation Ajax, which resulted in the overthrow of Prime Minister Mossadeq in 1953 and reinstatement of the Shah. Despite the Shah's modernization efforts, including granting women voting rights and initiating public housing and social security programs, his regime was known for its lack of political freedom and brutal repression of opposition, engendering widespread resentment among Iranians.
By the late 1970s, a combination of economic disarray, political repression, and societal demands for change led to the rise of Ayatollah Khomeini's influence, whose calls for strike and non-payment of taxes sparked massive protests. The culmination of these forces into the Iranian Revolution ultimately toppled the Shah's government. On January 16, 1979, the Shah fled Iran, and shortly thereafter, an Islamic republic was established, with the constitution mandating conformity to Islamic law.