The Goguryeo regime was established in the second year of the Jianshao era of the Western Han Dynasty by Jumong, a people of Buyeo, within the territory of Xuanju County under the Western Han.
In the fifth century, Goguryeo expanded south into the Korean Peninsula, occupying the regions of the Yesong River and the Han River basin. In 427 AD, it moved its capital to Pyongyang, competing with Baekje and Silla in the southern part of the Korean Peninsula—a period historically known as the "Later Three Han Period."
At this time, Goguryeo's territory spanned both China's northeastern region and the northern part of the Korean Peninsula.
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