Iran is home to one of the world’s oldest civilizations,beginning with the formation of the Elamite kingdoms in the fourth millennium BC. It was first unified by the Iranian Medes in the seventh century BC, and reached its greatest extent during the Achaemenid Empire founded by Cyrus the Great in the sixth century BC, stretching from Eastern Europe to the Indus Valley, becoming a larger empire than previously ever existed in the world.The Iranian realm fell to Alexander the Great in the fourth century BC, but reemerged shortly after as the Parthian Empire, followed by the Sasanian Empire, which became a leading world power for the next four centuries.
Arab Muslims conquered the empire in the seventh century AD, ultimately leading to the displacement of the indigenous faiths of Zoroastrianism and Manichaeism with Islam. Iran made major contributions to the Islamic Golden Age that followed, producing many influential figures in art and science. After two centuries, a period of various native Muslim dynasties began, which were later conquered by the Turks and the Mongols.
The rise of the Safavids in the 15th century led to the reestablishment of a unified Iranian state and national identity, which followed the country’s conversion to Shia Islam, marking a turning point in Iranian and Muslim history.
The country’s rich cultural legacy is reflected in part by its 21 UNESCO World Heritage Sites, the third-largest number in Asia and eleventh-largest in the world. Iran is a multicultural country comprising numerous ethnic and linguistic groups, the largest being Persians (61%), Azeris (16%), Kurds (10%), and Lur (6%).