Definition: The Parthian Empire existed from about 247 B.C. A.D. 224. It is thought that the founder of the Parthian empire was Arsaces I. The Parthian Empire was located in modern Iran, from the Caspian Sea to the Tigris and Euphrates Valley. The Sasanians, under Ardashir I (who ruled from A.D. 224-241), defeated the Parthians, thereby putting an end to the Parthian Empire.

