Islamic republic is the name given to several states in countries ruled by Islamic laws, including the Islamic Republics of Pakistan, Iran, Afghanistan, and Mauritania. Pakistan first adopted the title under the constitution of 1956. Mauritania adopted it on 28 November 1958. Iran adopted it after the 1979 Iranian Revolution that overthrew the Pahlavi dynasty. Afghanistan adopted it after the 2001 overthrow of the Taliban. Despite the similar name the countries differ greatly in their governments and laws. The term Islamic republic has come to mean several different things, some contradictory to others. To some Muslim religious leaders in the Middle East and Africa who advocate it, an Islamic Republic is a state under a particular Islamic form of government. They see it as a compromise between a purely Islamic Caliphate, and secular nationalism and republicanism. In their conception of the Islamic republic, the penal code of the state is required to be compatible with some or all laws of Sharia, and the state may not be a monarchy as many Middle Eastern states are presently.