Wikipedia
Goryeo, also known as Koryŏ (; ; 918–1392), was a Korean dynasty established in 918 by King Taejo. This kingdom later gave name to the modern exonym " Korea". It united the Later Three Kingdoms in 936 and ruled most of the Korean Peninsula until it was removed by the founder of the Joseon in 1392. Goryeo expanded Korea's borders to present-day Wonsan in the northeast (936–943), the Yalu River (993) and finally almost the whole of the Korean Peninsula (1374).
Two of this period's most notable products are celadon pottery and the Tripitaka Koreana—the Buddhist canon ( Tripiṭaka) carved onto more than 80,000 woodblocks and stored (and still remaining) at Haeinsa. The people of Goryeo also created the first metal movable type that was capable of printing actual books, in 1234; the oldest surviving metal movable type book, the Jikji, was printed in 1377.
In 668, Silla conquered Baekje and Goguryeo with an alliance with Tang China, but by the late 9th century it was tottering, its monarchs being unimaginative and pressed by the power of powerful statesmen. Many robbers and outlaws agitated and in 900 Gyeon Hwon revolted from Silla control in the Jeolla region as the state of Later Baekje; the year after, Gung Ye revolted from the northern regions as Taebong. A son of a regional lord, Wang Geon, joined Taebong as a general.
Taebong fell when Wang Geon revolted and killed Gung Ye in 918; he was crowned Taejo of Goryeo in June of the same year. Silla was overpowered by Goryeo and Later Baekje and surrendered to Goryeo in 935. In 936, Later Baekje surrendered and Goryeo subsequently maintained an unbroken dynasty that ruled Korea for 474 years, although the government was controlled by military regime leaders between 1170 and 1270.
By the late 13th century, Goryeo had lost much of its power due to the Mongols and their Yuan dynasty. Although King Gongmin managed to free his kingdom from the Yuan overlordship in the mid-14th century, General Yi Seonggye revolted and overthrew King Gongyang in 1392, establishing himself as Taejo of Joseon. Gongyang was killed in 1394.