Appointed by Nero in 61 AD to conduct the war more aggressively than Corbulo, Paetus arrived in the East with arrogance, boasting that he would not merely impose a king but directly annex Armenia as a Roman province. However, he lacked the military skill to back up his words.
In 62 AD, while Corbulo was defending the Syrian frontier, Paetus led two legions into Armenia. He dispersed his forces dangerously and failed to establish proper scouting or defenses. When King Vologases I advanced with a large Parthian army, Paetus was caught unprepared and besieged in his camp at Rhandeia.
Starving and demoralized, Paetus forced his troops to surrender on humiliating terms. The Roman legions were made to pass under the yoke (a symbol of subjugation) and evacuate Armenia immediately. Paetus was recalled to Rome, where Nero mockingly forgave him, saying he was 'pardoned immediately, lest someone so prone to panic might die of fear if kept in suspense.'