Persia emerged in the 6th century BC under the Achaemenid dynasty as a vast empire that controlled an area from India to Greece. It was conquered by Alexander the Great, but soon after Persia regained its independence in the form of the Parthian and Sassanid Empires. The latter was defeated by Islamic Arab forces in the 7th century AD, who were followed by Seljuk Turks, the Mongols, and Tamerlane.
Many dynasties have ruled Iran, the first of which was under the Achaemenids (559 - 330 BC), a dynasty founded by Cyrus the Great. After the Hellenistic period (300 - 250 BC) came the Parthian (250 BC - AD 226 ) and the Sassanid (226 - 651) dynasties.
The seventh century Arab-Muslim conquest of Iran was followed by conquests by the Seljuk Turks, the Mongols, and Tamerlane. Iran underwent a revival under the Safavid dynasty (1502-1736), the most prominent figure of which was Shah Abbas. The conqueror Nadir Shah and his successors were followed by the Zand dynasty, founded by Karim Khan, and later the Qajar (1795-1925) and the Pahlavi dynasties (1925-1979).