Political map of Europe & the Mediterranean 15 November 62 AD (Battle of Rhandeia): At first it appeared as though the Parthians might ignore the Roman intervention in Armenia (58–59 AD), but in 61 AD the new Armenian king (Tigranes VI of Armenia) attacked the Parthian client state of Adiabene. In retaliation, Shah Vologases (Vologases I of Parthia) invaded Armenia, restoring his brother Tiridates (Tiridates I of Armenia) to power. The Romans responded by sending in two armies, only to suffer a humiliating defeat when one of their commanders (Lucius Caesennius Paetus) was surrounded and forced to capitulate at Rhandeia (Battle of Rhandeia). At the peace treaty which followed (Treaty of Rhandeia), Rome agreed to acknowledge Tiridates as king of Armenia while Tiridates agreed to swear loyalty to Rome.