Early Iranian dynasties which re-asserted Iranian independence included the Tahirids, Saffarids, Samanids and Buyids.
The blossoming of Persian literature, philosophy, medicine, astronomy, mathematics and art became major elements of Muslim civilization. Iranian identity continued despite foreign rule in the ensuing centuries and Persian culture was adopted also by the Ghaznavid, Seljuk, Ilkhanid and Timurid rulers. The emergence in 1501 of the Safavid dynasty, which promoted Twelver Shia Islam as the official religion of their empire, marked one of the most important turning points in Iranian and Muslim history. The Persian Constitutional Revolution established the nation's first parliament in 1906, within a constitutional monarchy. In 1953 Iran became an authoritarian regime, following a coup d'état instigated by the UK and US. Growing dissent with foreign influence culminated during the Iranian Revolution which led to establishment of an Islamic republic on 1 April 1979.
Iran is a founding member of the UN, NAM, OIC and OPEC. The political system of Iran, based on the 1979 constitution, comprises several intricately connected governing bodies. The highest state authority is the Supreme Leader. Shia Islam is the official religion and Persian is the official language
