Wang Geon was from a gentry family in Song-ak (Gaeseong). His family had accumulated wealth through maritime trade. Under Gungye, Wang Geon advanced to a high rank. Later, when Gungye was driven from his throne for his tyranny, it was Wang Geon who was put forward to succeed Gungye. Wang Geon named the state Goryeo and moved the capital from Cheolwon to Songak.
Wang Geon employed a policy of friendship with Silla, but confronted Later Baekje. When Later Baekje attacked Silla, Wang Geon offered support. Silla, which was in crisis, ultimately surrendered itself to Goryeo. Meanwhile, in Baekje, there were internal disputes regarding the succession of the throne. When Gyeon Hweon’s eldest son confined him and took the throne for himself, Gyeon Hweon escaped and entrusted himself to Wang Geon. At this juncture, Goryeo attacked Later Baekje, brought the nation down, and finally reunited the nation into the Later Three Kingdoms (936). Wang Geon was able to become the central figure in the unification of the Later Three Kingdoms because he had the support of the local gentry families, as well as the general populace. He was a virtuous leader who disregarded his own importance, regarded others highly. and warmly took care of the people. The local gentry leaders soon began to follow Wang Geon.
Through his marriage policies, he forged ties with the powerful clans. He reinforced the alliance by bestowing them his surname“ Wang”, thus treating them as family members. Wang Geon also reduced the burden of heavy taxes for the commoners, helped the poor, released those who had wrongfully become slaves, and thus won great admiration of the populace. The unification of the Three Kingdoms by Silla was incomplete in that it lost the ancient territories of Goguryeo and led to the existence of Balhae in the north that succeeded Goguryeo. The reunification by Goryeo, however, was a complete version of national unification encompassing the diverse powers of the former Three Kingdoms, as well as the people of Balhae. Accordingly, Goryeo provided the momentum under which the people of Korea could achieve unification in the political, social and cultural spheres and start a renewed development.