The Three Kingdoms of Korea or Samguk competed for hegemony over the Korean Peninsula during the ancient period of Korean history. During the Three Kingdoms period, many states and statelets consolidated until, after Buyeo was annexed in 494 and Gaya was annexed in 562, only three remained on the Korean Peninsula: Goguryeo, Baekje and Silla. The "Korean Three Kingdoms" contributed to what would become Korea; and the Goguryeo, Baekje and Silla peoples became the Korean people.

Goguryeo also later known as Goryeo, was a Korean kingdom which was located in the northern and central parts of the Korean Peninsula and the southern and central parts of modern day Northeast China. At its peak of power, Goguryeo conquered most of the Korean Peninsula and large parts of Manchuria, along with parts of eastern Mongolia, Inner Mongolia, and modern-day Russia.