Taejo (Korean: 태조; Hanja: 太祖; 31 January 877 – 4 July 943), personal name Wang Kŏn (왕건; 王建), also known as Taejo Wang Kŏn (태조 왕건; 太祖 王建; lit. ''Great Progenitor Wang Kŏn''), was the founder of the Goryeo Dynasty of Korea. He ruled from 918 to 943, achieving unification of the Later Three Kingdoms in 936.
Wang Kŏn was born in 877 to a powerful maritime merchant family of Goguryeo descent based in Songak (modern Kaesong) as the eldest son of Wang Ryung. According to the Pyeonnyeon tongnok (편년통록; 編年通錄), quoted in the Goryeosa, Wang Kŏn's grandfather Chakchegon was the son of Emperor Suzong of Tang. According to the Encyclopedia of Korean Culture and the Doosan Encyclopedia, this is hagiographical. The Pyeonnyeon tongnok (c. late 12th century) said: While on a sea voyage to meet his father, Emperor Suzong of the Tang dynasty, 16-year-old Chakchegon encountered a dragon king, slayed a shape-shifting fox, and married a dragon woman; the dragon woman later transformed into a dragon and went away. According to the Seongwollok (성원록; 聖源錄), quoted in the Goryeosa, the "dragon woman" was a daughter of Tu Ŭn-chŏm from Pyongju (modern-day Pyongsan County). The story that Wang Kŏn was descended from either Suzong or Xuanzong was dismissed by the Joseon compilers of the Goryeosa. Modern historians believe that Wang Kŏn's ancestors were influential Goguryeoic hojoks (lords) that conducted maritime trade with China for generations. According to the Gaoli tujing (c. early 12th century) written by the Song dynasty envoy Xu Jing, Wang Kŏn's ancestors were Goguryeo nobility. According to Jang Deokho, his ancestors were Goguryeo refugees who settled around Songak, accumulating great wealth through maritime trade and gaining control of the region, including the Ryesong River. During the Later Silla period, the northern regions, including Songak, were the strongholds of Goguryeo refugees, and Wang Kŏn's hometown of Songak would become the original capital of Later Goguryeo in 901.
According to a document created during the reign of King Uijong of Goryeo, the Sillan monk Doseon prophesied that Wang Kŏn would rise to power and become king after visiting Wang Kŏn's father.
Wang Kŏn began his career in the turbulent Later Three Kingdoms. In the later years of Silla, many local leaders and bandits rebelled against the rule of Queen Jinseong, who did not have strong and wise enough leadership or policies to improve the poor condition of the people. Among those rebels, Kung Ye of the northwestern region and Kyŏn Hwŏn of the southwest gained more power. They defeated and absorbed many of the other rebel groups as their troops marched against local Silla officials and bandits. In 895, Kung Ye led his forces into the far northwestern part of Silla, where Songdo was located. Taejo's father, Wang Ryung, along with many local clans, quickly surrendered to Kung Ye. Wang Kŏn followed his father into service under Kung Ye, the future leader of Taebong, and he began his service under Kung Ye's command.
Wang Kŏn's ability as a military commander was soon recognized by Kung Ye, who promoted him to general and even regarded him as his brother. In 900, he led a successful campaign against local clans and the army of Later Baekje in the Chungju area, gaining more fame and recognition from the king. In 903, he led a famous naval campaign against the southwestern coastline of Later Baekje at Keumsung, later Naju, while Kyon Hwon was at war against Silla. He led several more military campaigns, and also helped conquered people who lived in poverty under Silla rule. The public favored him due to his leadership and generosity.
In 913, he was appointed as prime minister of the newly renamed Taebong. Its king, Kung Ye, whose leadership helped found the kingdom but who began to refer to himself as the Buddha, began to persecute people who expressed their opposition against his religious arguments. He executed many monks, then later even his own wife and two sons, and the public began to turn away from him. His costly rituals and harsh rule caused even more opposition.
Rise to the throne and founding of Goryeo
In the night of July 24, 918, four top-ranked generals of Taebong—Hong Yu (홍유; 洪儒), Pae Hyŏn-gyŏng (배현경; 裵玄慶), Sin Sung-gyŏm and Pok Chigyŏm (복지겸; 卜智謙)—met secretly and agreed to overthrow Kung Ye's rule and crown Wang Kŏn as their new king. Wang Kŏn first opposed the idea but later agreed to their plan. Kung Ye was overthrown in a coup and killed near the capital, Cheorwon. On the sunrise of the next day, the generals installed Wang Kŏn as the new king. Taejo renamed the kingdom Goryeo, thus beginning the Goryeo Dynasty. The next year he moved the capital back to his hometown, Gaegyeong.
He promoted Buddhism as Goryeo's national religion, and laid claim to the northern parts of the Korean Peninsula and Manchuria, which he considered his rightful legacy as the successor of Goguryeo. According to the Goryeosa, in 918, the ancient capital of Pyongyang had been in ruins for a long time and foreign barbarians were using the surrounding lands as hunting grounds and occasionally raiding the borders of Goryeo; therefore, in his first year as king, Wang Kŏn ordered his subjects to repopulate the ancient capital, and soon sent his cousin Wang Sing-nyŏm to defend it. Afterward, he decreed Pyongyang as the Western Capital. He also sought alliances and cooperation with local clans rather than trying to conquer and bring them under his direct control.
The War of the Later Three Kingdoms
In 927, Kyon Hwon of Later Baekje led his forces into Silla's capital, Gyeongju, capturing and executing its king, King Gyeongae. Then he established King Gyeongsun as his puppet monarch before he turned his army toward Goryeo. Hearing of the news, Taejo planned a strike with 5,000 cavalrymen to attack Kyon's troops on the way back home at Gongsan near Daegu in the Battle of Gongsan. He met the Later Baekje army and suffered a disastrous defeat, losing most of his army including his generals Kim Nak and Sin Sung-gyom, the very same man who crowned Wang as a king. According to the legend, Taejo and Sin Sung-gyom exchanged their armor so that the king would be able to escape the battlefield. While Wang Kŏn escaped the battlefield, Sin and the remaining army fought bravely against the Later Baekje army. But eventually his army was routed and in the woods Sin was shot with arrows and was killed by the enemy. Taejo escaped from this mountain and fled alone to the mountain Apsan, and he spent a few days hiding in a large cave at the peak of Apsan. While Taejo retreated from the battle and fled to Apsan Mountain, he left many place names related to him in Daegu. However, Goryeo quickly recovered from defeat and successfully defended Later Baekje's attack on its front.
In 935, the last king of Silla, King Gyeongsun, felt there was no way to revive his kingdom and surrendered his entire land to Taejo. Taejo gladly accepted his surrender and gave him the title of prince, and accepted his first cousin as his fifth wife and queen (Wang had six queens, and many more wives as he married daughters of every single local leader). In turn, King Gyeonsun married King Taejo's eldest daughter, Princess Nakrang, whose daughter also intermarried into the royal Wang clan through her marriage with King Gyeongjong; the grandson of King Taejo and Queen Sinmyeong.
It caused much disgust to Kyon Hwon. Kyon's father, Ajagae, who held his own claim to the Sangju region, also defected and surrendered to Goryeo and was received as the father of a king.
In the same year, Kyon Hwon's oldest son, Kyŏn Sin-gŏm, led a coup with his brothers Yang-gŏm and Yong-gŏm, against their father, who favored their half-brother, Kŭm-gang, as his successor to the throne. Kyon Hwon was sent into exile and imprisoned in the temple of Geumsansa, but escaped to Goryeo and was treated like Taejo's father, who died just before his surrender.
Goryeo victory and unification
In 936, Wang led his final campaign against Sin-gom of Later Baekje. Sin-gom fought against Taejo, but facing much disadvantage and inner conflict, he surrendered to Taejo. Wang finally conquered Later Baekje, and unified the nation for the second time since Unified Silla; he ruled until 943, and died from disease.