133 BC-AD 223 Parthian

Mithradates I (171-138 BC) established the Iranian Parthian Empire, which stretched from Central Asia through Iran to Syria. The Parthian Empire flourished from the time of Mithradates II (124-87 BC) to the end of the 1st century AD. During this time, Roman power expanded eastwards from the Mediterranean and a frontier between the two powers was established at the River Euphrates. The Parthians resisted further Roman expansion, inflicting major defeats on Roman armies and establishing their authority over Armenia and often over Syria as far as the Roman city of Antioch.

Control of the trade routes across Iran and the Persian Gulf to Arabia, Central Asia and India brought immense prosperity to Parthia. However, during the 2nd century AD the growth of the powerful Kushan Empire in Afghanistan and Central Asia endangered Parthian trade. The Romans encouraged this economic threat to Parthia. Invasions by nomadic groups helped to weaken Parthia further. The Romans were able to extend their power east of the Euphrates and they sacked the Parthian capital of Ctesiphon three times. Parthia never recovered from this and the last Parthian king was defeated in AD 224 by Ardashir, a local ruler from the city of Istakhr (near Persepolis in southern Iran) who established the Sasanian Empire.