Ancient land, southwestern Asia.
Corresponding roughly to modern northeastern Iran, it formed a province of the Persian Achaemenian dynasty and later of the empire of Alexander the Great . After the dissolution of the Seleucid dynasty с 250 BC, a new Parthian kingdom was founded by Arsaces. The Arsacid dynasty ruled until it was overthrown by the Sāsānian dynasty с AD 226. At its height in the early 1st century BC, it was known as the Parthian empire and included the area between the Indus rivers and between the {{link=Amu Darya">Amu Darya and the Arabian Sea. It was weakened by internal disorder and by conflict with Rome in the 1st century BC. One of its later capitals was Hecatompylos . The ruins of Ctesiphon , another major Parthian city, are in modern Iraq, near Baghdad. The Parthians were famous as horsemen and archers.