In 238, Sima Yi was dispatched to command a military campaign against Gongsun Yuan of the self-proclaimed Yan Kingdom in Liaodong, resulting in Sima Yi's capture of his capital Xiangping and massacre of his government. Between 244 and 245, General Guanqiu Jian was dispatched to invade Goguryeo and severely devastated that state. The northeastern frontier of Wei was now secured from any possible threats. 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 Korea that formed much of Goguryeo's economy. Although the king evaded capture and eventually settled in a new capital, Goguryeo was reduced to such insignificance that for half a century there was no mention of the state in Chinese historical texts.