"Mohammed Reza Pahlavi was the shah of Iran from 1941 to 1979, except for a brief period in 1953 when Prime Minister Muhammed Mosaddeq overthrew him. Mosaddeq was in turn overthrown with assistance from the U.S., and the shah was returned to power as a U.S. ally. He greatly modernized Iran and established social reforms, many of which angered fundamentalist religious leaders. In 1979 the religious opposition, lead by Ayatollah Ruhollah Khomeini, drove the shah into exile. Khomeini sought the capture of the shah, and when it was learned that he had been admitted into the United States for medical treatment, Iran's response was the start of the hostage crisis at the U.S. embassy in Teheran. After dismissal from the hospital the Shah fled to Panama, then Egypt. He died on July 27, 1980, at the age of 60."