On February 11, 1979, the Iranian monarchy collapsed after months of nationwide strikes and mass protests. Shah Mohammad Reza Pahlavi had fled on January 16. Ayatollah Ruhollah Khomeini returned from 15 years of exile on February 1. Armed forces declared neutrality on February 11, ending the Shah's government. A referendum on April 1 established the Islamic Republic with 98 percent approval. The revolution united leftists, nationalists, and Islamists against the Shah's autocracy and Western influence. Iran subsequently held 52 American diplomats hostage for 444 days from November 4, 1979 to January 20, 1981.