Buyeo in the context of "Liaodong Commandery"

The Three Kingdoms of Korea or Samhan (Goguryeo, Paekche and Silla) competed for hegemony over the Korean Peninsula during the ancient period of Korean history. During the Three Kingdoms period (Korean: 삼국 시대), 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, Paekche and Silla. The "Korean Three Kingdoms" contributed to what would become Korea; and the Goguryeo, Paekche and Silla peoples became the Korean people.

The three kingdoms occupied the entire peninsula and roughly half of Manchuria (modern-day Northeast China and small parts of the Russian Far East). Goguryeo controlled the northern half of the peninsula, as well as Liaodong Peninsula and Manchuria. Paekche and Silla occupied the southern half of the peninsula. The island kingdoms of Tamna and Usan were subordinated to Paekche and Silla, respectively.

Eastern Buyeo, also rendered as Dongbuyeo or Eastern Fuyu, was an ancient kingdom that developed from Northern Buyeo (Northern Fuyu), until it was conquered by Goguryeo. According to the Samguk Sagi, it was established when the Buyeo king Hae Buru moved the capital eastward by the sea.

Yemaek or Yamaek 濊貊 were a people of Koreans who resided in ancient Manchuria. Whether they were: homogenous; heterogenous of Ye 濊 and Maek 貊; or whether Yemaek were a branch of Maek remains debated. However, the most accepted model is that they were ethnolinguistically identical but remained socially and politically disparate identities. The first Yemaek state to appear were 朝鮮 (Joson) that fell in 108 BC. They were renamed Old Joson after Joson Kingdom were later founded in 1392 AD: ostensibly as a successor state to Old Joson. Yemaek together with Han 韓 acted as the foundations for the formation of the Korean national identity. Of the three kingdoms who succeeded in forming centralised bureaucracy, 高句麗 (Gogooryo) had the strongest connection with Yemaek whereas 新羅 (Silla) had stronger Han identity and 百濟 (Baekje) were considered something in-between. Thus, the study of Yemaek is inevitably centralised around Gogooryo.

It remains controversial whether Gogooryo were: Ye; Maek; Yemaek; a branch of Yemaek; or Ye whose exonym were Maek due to sparse indigenous sources. However, it does appear Gogooryo had been an accumulation of many peoples such as Daesoo Maek (大水貊), Sosoo Maek (小水貊) and purportedly Yang Maek (梁貊). Furthermore, people who resided in the river basin of Amnok River began to be referred to as Maek somewhere near Anno Domini and it's hypothesised they amalgamated with Ye whom migrated from Booyo. They further accelerated their expansion by further conquering nearby tribes, thus forming a unified Yemaek identity under one sovereign.