Why did Mohammad Reza Shah Pahlavi leave Iran in January 1979?

Mohammad Reza Shah Pahlavi left Iran on January 16, 1979, as the Iranian Revolution reached a critical turning point. His departure was driven by the following factors:

• Widespread Unrest: Throughout 1978, the shah faced escalating protests from a broad coalition of Iranians, including Shiʿi clergy, students, bazaar merchants, and the urban working class. These groups were united in their opposition to his autocratic rule, government corruption, and the perceived negative impacts of forced Westernization.123
• Cycle of Violence: The regime’s attempts to suppress dissent through force, including the imposition of martial law, only fueled further protests. A cycle of violence emerged where government-inflicted casualties led to mourning processions that sparked even larger demonstrations.24
• Personal Health and Vacillation: The shah was weakened by cancer and appeared stunned by the intensity of the public hostility. He vacillated between concession and repression, often viewing the uprising as an international conspiracy rather than a domestic movement.24
• Loss of Control: As the revolution gained momentum, the shah’s authority collapsed, leading to the failure of successive governments. He eventually appointed Shahpur Bakhtiar as prime minister before fleeing the country under the official guise of a "vacation".24