Taejo (r. 918-943 CE), previously known as Wang Geon or Wang Kon, was the founder and first king of the Goryeo (Koryo) kingdom which unified and ruled ancient Korea from 918 CE to 1392 CE. Wang Geon was given the posthumous title of Taejo meaning 'Great Founder.' His dynasty would oversee an unprecedented flourishing of Korean culture, and its name is the origin of modern Korea's English name.
The Fall of Silla
The Unified Silla Kingdom (668- 935 CE) had held sway over the Korean peninsula for three centuries, but the state was in a slow decline. Rebellions from the peasantry and the aristocracy were rife, and there followed a period of political turmoil referred to as the Later Three Kingdoms period (889-935). Gyeon Hwon, a peasant leader, took advantage of the political unrest in 892 CE and formed a revival of the old Baekje kingdom in the south-west portion of the peninsula. Meanwhile, an aristocratic Buddhist monk leader, Gung Ye declared a new Goguryeo state in the north in 901 CE, known as Later Goguryeo. Gung Ye was assisted by his first minister and general Wang Geon, the son of a wealthy merchant and local headman at Gaeseong in the Silla kingdom.