A "shah" is a title used for a king or ruler in Persian-speaking regions, particularly in Iran. The term has historical significance, as it has been used by various dynasties throughout Persian history, symbolizing authority and governance. The role of a shah often included overseeing the administration, military, and cultural affairs of the state. The most notable modern example of a shah is Mohammad Reza Pahlavi, the last ruler of Iran, who reigned from 1941 until the 1979 Iranian Revolution. His reign was marked by significant modernization efforts, but also faced criticism and opposition, leading to his eventual exile and the establishment of the Islamic Republic of Iran.