The Three Kingdoms Period

Early Korean settlements developed south of the Han River relatively isolated from the Asian continent. Because of this, the early Korean people were able to develop independently without early involvement with events on the continent, at least for the earlier periods of Korean development. Around the middle of the third century A.D., the Chinese began to become a serious threat which became a powerful force in unify much of the tribes in the southern …

…combined forces of Silla and the Tang Dynasty of China eventually destroyed Koguryo. Koguryo's ally, Paekche, fell to Silla and the Tang Dynasty in 660 A.D. Silla and the Tang Dynasty then attacked Koguryo for eight years who eventually fell. Silla unified Korea in 668 A.D., but Silla's had to eventually force the Chinese out of their territory, which they did. However, because of this, they lost all the land north of the Taedong River.