Koguryo thrived for 705 years from 37 B.C., when it was founded to A.D. 668, when it collapsed, and its historical achievements was the source of enormous pride to its descendants. Like most nations from that time, Koguryo started out from a modest beginning at the Zolbon area in the Yalu River valley.

The founder of Koguryo was King Chumo, or Gojumong, who originally came from the State of Buyeo. When he left Buyeo and founded Koguryo, Gojumong was so hard pressed to afford a decent palace or secure sufficient grain output. Furthermore, the fledgling state was surrounded by stronger nations like Biryu, Seonbi, and Buyeo. So, unless one was strong enough, a weak nation was destined to subjugation to others as a feudal state. Soon, however, Koguryo developed strong leadership and military power, and began to pursue a policy of expansion by conquering smaller nations one by one. Conquering small neighboring nations like Biryu, Okjeo, Haeng-in and Yangmaek, Koguryo grew up to be a strong country that even overpowered Buyeo by the early first century A.D.

By the middle of the first century A.D., during King Taejo's reign, Koguryo was able to absorb various foreign cultural elements on top of the cultural foundations of preceding kingdoms of Old Joseon (Korea) and Buyeo and established itself as a stable state with a systematic ruling structure. King Taejo successfully advanced into Liaodong and the plains of the northern Korean peninsula by attacking Later Han's eastern Commanderies of Lolang, Xiantu and Liaodong, driving them out toward the west.

In 246, however, Koguryo had to suffer a humiliating defeat and its capital temporarily fell into enemy hands when forces from China's Wei attacked it from the west. It soon regained its national strength and was able to repulse repeated subsequent attacks from Wei. Koguryo continued to grow up and held sway over Buyeo and Suksin in the north, and by the early fourth century,