By the first century BCE, Korea was divided into three powerful kingdoms:
-Goguryeo(northern Korea and Manchuria)
-Baekje(southwestern Korea)
-Silla(southeastern Korea)
These kingdoms frequently competed for dominance, developing centralized governments and military systems. In 668 CE, Silla, with the help of China’s Tang dynasty, unified most of the peninsula, forming the Unified Silla period. In the north, the kingdon of Balhae emerged, continuing the legacy of Goruryeo.