Iran officially became the Islamic Republic on April 1, 1979

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3 REVOLUTIONS

Iran officially became the Islamic Republic on April 1, 1979, following a national referendum after the Islamic Revolution, which overthrew the monarchy and established a new theocratic system led by Ayatollah Ruhollah Khomeini as Supreme Leader. This date is celebrated annually as Islamic Republic Day in Iran. 

The Revolution: The revolution began in January 1978, culminating in the Shah leaving Iran in January 1979 and Khomeini assuming control.

• The Referendum: A nationwide vote in April 1979 overwhelmingly approved the establishment of an Islamic republic, creating a new constitution that integrated religious scholars atop the government structure.