Goguryeo–Wei WarKorean Peninsula
The Goguryeo–Wei War was a series of invasions of Goguryeo from 244 to 245 launched by Cao Wei.
The invasions, a retaliation against a Goguryeo raid in 242, destroyed the Goguryeo capital of Hwando, sent its king fleeing, and broke the tributary relationships between Goguryeo and the other tribes of the Korean Peninsula that formed much of Goguryeo's economy. Although the king evaded capture and would go on to settle in a new capital, Goguryeo was greatly diminished for a time, and would spend the next half century rebuilding its ruling structure and regaining control over its people, unmentioned by the Chinese historical texts.
By the time Goguryeo reappeared in Chinese annals, the state had evolved into a much more powerful political entity—thus the Wei invasion was identified by historians as a watershed moment in Goguryeo history that divided the different stages of Goguryeo's growth. In addition, the second campaign of the war included the furthest expedition into Manchuria by a Chinese army up to that time and was therefore instrumental in providing the earliest descriptions of the peoples who lived there.