In 1978, the unrest in Iran against the pro-U.S. monarch, Shah Mohammad Reza Pahlavi, and his autocratic rule boiled over into a revolution. In January 1979, the Shah fled Iran to exile in Egypt and Iran was turned into an "Islamic Republic." On 22 October 1979, the Shah was allowed to travel to the United States for further medical treatment, causing widespread anger in Iran. Furious at what was called "evidence of American plotting" by the Iranian revolutionaries, the American Embassy in Tehran was taken over by a group of armed revolutionaries in violation of accepted diplomatic practices and international law, with the entire staff becoming hostages. While the situation was trying to be resolved through diplomatic means, no real progress was gained for the release of the hostages. In a bold plan, U.S. military forces were instructed to come up with a course of action to go into Iran and free the hostages by force of arms.