Yi Sng-gye (1335-1408) was the founder of the Yi dynasty, which lasted until 1910. An able military leader, he unified Korea under Chinese suzerainty.
Yi Sng-gye was born in modern Ynghung, the second son of Yi Chach'un. Yi's family, originally said to be of Chnju in the south, moved to the northeast in the second half of the 13th century. This migration was undertaken by Yi's great-great-grandfather, who later held a Mongol office. Yi's father is mentioned in the official annals for the first time in 1355, when he arrived in the capital to pay homage to King Kongmin. Later, when the King initiated a campaign to free himself from the Mongol occupation and to regain Korean territories in the north, Yi Chach'un received royal orders and participated in the successful campaign.
Thus Yi Sng-gye's ancestors were Kory nationals who had served the Mongols in the northeast. Because of geographical proximity, they were in contact not only with the Mongols but with the Jürchen tribes and were familiar with their manners and customs. Raised in such surroundings, Yi excelled in equestrian archery from his boyhood.
Yi held his first office in 1361; in December he repulsed the Red Turbans, recapturing the capital from these Chinese rebels. In 1362 he annihilated the forces of the Mongol general on the plain of Hamhung and in 1364 suppressed the rebellion of a Kory traitor who fled to the Mongols. In 1370, as the general of the northeast, he marched north to destroy the Mongol garrisons and to sever relations with the Northern Yüan. His troops went deep into the enemy territory, to the right bank of the T'ung-chia River, and captured the enemy stronghold. As a consequence of these campaigns, his name was dreaded by the Mongols and Jürchen alike.
His military genius was equally manifested in his campaigns against the Japanese pirates in the south. The coastal raids of the Japanese, begun in 1232, became more frequent and disastrous under the reign of the third-last ruler of Kory. There were a series of successful campaigns in 1371, 1377, and 1378; but the most famous was that in 1380, when Yi Sng-gye attacked the pirates, cornered them at Mt. Hwang, and annihilated them. After filling a number of important posts, Yi was promoted in 1388 to vice-chancellor, and his name and fame were firmly established at court and abroad.
Perhaps the most dramatic decision taken by Yi before his enthronement was his refusal to march north to drive out Ming garrisons in Liaotung (1388). Instead, he and his army turned back from Wihwa Island, thus inflicting a deadly blow on the waning Kory dynasty and its pro-Mongol faction. It was the culmination of a chain of events begun in 1374.
Although Sino-Korean relations immediately after the founding of Ming were friendly, two events that took place in 1374 overshadowed these relations: the assassination of King Kongmin by eunuchs (October 19), and the murder of the returning Ming envoy by a Korean escort (December 28). These events caused the Ming founder to be suspicious of Korean sincerity, and he prohibited receiving Korean envoys. Those sent on numerous occasions were turned back at Liaotung (1374-1378), and those who managed to reach Nanking were banished or imprisoned. Despite the Emperor's ill-treatment of envoys and his exorbitant demand of tribute horses, Kory continued to demonstrate its goodwill.
However, the Chinese emperor continued to make unreasonable demands, such as the purchase of 5,000 Korean horses, and the drawing of the Ming-Korean border far below the Yalu, on the border of modern Kangwn and Hamgyng provinces. The latter proposal particularly disturbed the Korean court, which decided to march to Liaotung to destroy Ming garrisons there. Upon recrossing the Yalu and marching back to the capital, Yi Snggye banished the war advocates and took the helm of state affairs.
Yi's progressive pro-Ming party, comprising mainly students of Neo-Confucianism, set out to remove the sources of future worries. Since the two rulers from the last dynasty were descendants of an evil monk and hence not of the legitimate royal line, Yi and his supporters had them banished and later executed. King Kong-yang was installed in their place (1389). They then enforced a land reform in 1389 and burned the land registers of the old Kory nobility in the following year. The last step was the assassination of the Kory loyalist Chng Mong-ju on the night of April 26, 1392, thus removing the last obstacle to final victory. On July 31 the last Kory king was sent into exile, and five days later Yi ascended the throne.
Yi's enthronement meant the victory of the pro-Ming and anti-Buddhist party, whose members were mostly supporters of the newly imported Neo-Confucianism. The new dynasty, therefore, rejected Buddhism, which had been the state religion for over 800 years, as subversive of public morality and adopted Neo-Confucianism as its official political philosophy. It also adopted the Confucian concept of the "heavenly mandate" as a means of emphasizing the legitimacy of the dynasty.
The "meritorious subjects," who had assisted in the revolution and framed and executed the new policy, set out to compose eulogies to win the minds of men. Such poems praised not only the cultural and military accomplishments of the founder but also the beauty of the new capital, Seoul. In 1396 city walls were constructed around the capital. Yi and his ministers remodeled political and cultural institutions and reinstated and perfected the civil service examination system. In order to legalize new institutions, a set of codes and statutes was compiled. Envoys from the Liu-ch'iu Islands (1392, 1394, 1397) and from Siam (1393) arrived to pledge their allegiance.
Soon after his ascension of the throne, Yi sent envoys to Nanking informing the Ming of the dynastic change. He also requested the Ming founder to select the new name for Korea. Thereupon, the Emperor chose Chosn ("brightness of the morning sun"), a most beautiful and fitting name for Korea, which was adopted on March 27, 1393.
However, owing to matters concerning Korean-Jürched relations and yearly tribute, friendly relations were not easily established. The Ming emperor accused Korea of influencing Ming border officials, of enticing the Jürchen to cross the Yalu and violate Ming territory, and of sending weak horses as tribute. Several missions sent to exculpate Korea of these charges were unsuccessful, until Yi's third son went to Nanking (1394). Sino-Korean relations were, however, normalized only in 1401, when Ming envoys brought investiture and the golden seal of the "King of Korea."
When the investiture belatedly came (1401), Yi had already abdicated in favor of his second son, who was in turn succeeded by Yi's third son. Yi died on June 18, 1408. He had eight sons and five daughters.
A forthcoming English publication by Peter H. Lee will be titled Songs of Flying Dragons, a critical study of the eulogy cycle compiled to praise the founding of the Yi dynasty. For background on Yi Sng-gye's life and reign see Takashi Hatada, A History of Korea (1951; trans. 1969), and Edwin O. Reischauer and John K. Fairbank, A History of East Asian Civilization, vol. 1: East Asia: The Great Tradition (1958). □