The Parthian Empire, also known as the Arsacid Empire, was a major Iranian political and cultural power centered in ancient Iran from 247 BC to 224 AD. Its latter name comes from its founder, Arsaces I, who led the Parni tribe in conquering the region of Parthia in Iran's northeast, then a satrapy (province) under Andragoras, who was rebelling against the Seleucid Empire. Mithridates I greatly expanded the empire by seizing Media and Mesopotamia from the Seleucids. At its height, the Parthian Empire stretched from the northern reaches of the Euphrates, in what is now central-eastern Turkey, to present-day Afghanistan and western Pakistan. The empire, located on the Silk Road trade route between the Roman Empire in the Mediterranean Basin and the Han dynasty of China, became a center of trade and commerce.

The history of Iran is intertwined with that of Greater Iran, a sociocultural region spanning the area between Anatolia in the west and the Indus River and Syr Darya in the east, and between the Caucasus and Eurasian Steppe in the north and the Persian Gulf and the Gulf of Oman in the south. Central to this area is the modern-day country of Iran, which covers the bulk of the Iranian plateau.