Armenia reached its greatest size and influence under King Tigranes II. It went from the Mediterranean Sea northeast to the Kura River. The Artaxiads were overthrown by the Romans in AD 12. This started a period of civil war. After AD 54, the kingdom was ruled by the Arsacid Dynasty. In AD 387, Armenia was divided into Byzantine Armenia in the west and Persian Armenia in the east. Persian Armenia remained under the rule of Arsacid client kings until AD 428.