Corbulo vs Yeon Gaesomun

Corbulo was appointed governor of Cappadocia and Galatia with command against the Parthians in Armenia. He reorganized the Roman army, restored discipline, and captured the Armenian capital Artaxata, installing a Roman client king.

Corbulo captured the Armenian city of Tigranocerta after a siege. The city surrendered without a major battle. Corbulo then crowned Tigranes VI as king of Armenia, a Roman client, solidifying Roman influence in the region.

After the Parthians reasserted control over Armenia, Corbulo was ordered to withdraw. He negotiated a compromise with the Parthian king Vologases I, agreeing that a Parthian prince, Tiridates, would rule Armenia as a Roman client, ending the war.

Nero, suspicious of Corbulo's popularity and military success, summoned him to Greece and ordered his execution. Corbulo was forced to commit suicide. His death removed a potential rival but also a capable general from the Roman command.

Yeon Gaesomun led a military coup, killing King Yeongnyu and hundreds of nobles. He installed King Bojang as a puppet ruler and assumed the position of Dae Mangniji (Supreme Commander), establishing a military dictatorship over Goguryeo.

Yeon Gaesomun refused to submit to Tang Chinese demands for tribute and recognition, asserting Goguryeo's sovereignty. His aggressive stance led to multiple Tang invasions and a prolonged war that drained both empires.

Yeon Gaesomun led the defense of Ansi Fortress against a massive Tang Chinese invasion led by Emperor Taizong. The Goguryeo forces held out for months, inflicting heavy casualties and forcing the Tang army to retreat, preserving Goguryeo's independence.

Yeon Gaesomun died, leading to a power struggle among his sons. This internal division weakened Goguryeo, allowing the Tang-Silla alliance to conquer the kingdom in 668, ending its 700-year history.