Iran, with its long history of early cultures and empires, had suffered particularly hard during the Late Middle Ages and the early modern period. Many invasions of nomadic tribes, whose leaders became rulers in this country, affected it negatively.[5]
Iran was reunified as an independent state in 1501 by the Safavid dynasty, which set Shia Islam as the empire’s official religion,[6] marking one of the most important turning points in the history of Islam.[7] Functioning again as a leading world power, this time amongst the neighbouring Ottoman Empire, its arch-rival for centuries, Iran had been a monarchy ruled by an emperor almost without interruption from 1501 until the 1979 Iranian Revolution, when Iran officially became an Islamic republic on 1 April 1979.[8][9]