Menurut buku sejarah Kerajaan [[Koryo]], [[Samguk sagi]], Koguryo didirikan oleh raja [[Jumong]] yang berasal dari suku [[Buyo]] pada tahun 37 sebelum masehi. Pada saat itu wilayah Manchuria didiami oleh berbagai suku seperti Yemaek dan Buyo.
Goguryeo developed from a league of various Yemaek tribes to an early state and rapidly expanded its power from their original basin of control in the Han river drainage. The Goguryeo homeland was said to be mountainous and lacked arable land and could barely feed its own population. Goguryeo was known for being fond of raiding their neighbors so they could expand their resource base. In the time of King Taejo of Goguryeo in 53 CE, five local tribes were reorganized into five centrally ruled districts of the kingdom. Foreign relations and the military were controlled by the king. Aggressive military activities may have allowed Goguryeo to exact tribute from their tribal neighbors and to even dominate them politically and economically [13].
King Taejo conquered the Okjeo tribes of Northeast Korea as well as the Eastern Ye and other tribes in Southeastern Manchuria and Northern Korea. From the increase of resources and manpower that these subjugated tribes gave him, Goguryo attacked Han China's commanderies of Lelang, Xuantu, and Liaodong in the Korean and Liaodong peninsulas, becoming fully independent from the Han commanderies [14].
Generally, Taejo allowed the conquered tribes to retain their chieftains, but report to governors who were related to Goguryeo's royal line and were expected to provide heavy tribute. Taejo and his successors channeled these increased resources to continuing its expansion to the northwest. New laws regulated peasants and the aristocracy, as tribal leaders continued to be absorbed into the central aristocracy. Royal succession changed from fraternal to patrilineal, strengthening the royal court [15].
The expanding Goguryeo kingdom entered into direct military contact with the Liaodong commandery. Pressure from Liadong forced Goguryeo to move their capital in the Hun River valley to the Yalu River valley near Mt. Wandu.[16]
