The Imperial State of Iran, officially known in the Western world as the Imperial State of Persia until 1935 and commonly referred to as Pahlavi Iran, was the Iranian state under the rule of the Pahlavi dynasty. The dynasty was established in 1925 and lasted until 1979, when it was overthrown during the Iranian Revolution, ending the over 2,500-year-old Iranian monarchy and leading to the establishment of the Islamic Republic of Iran.