Early life

Kim Jong-seo was born in 1383 in Yanggwang-do, Gongju as the son of Kim Su and Lady Bae of the Seongju Bae clan. He was the second of 3 brothers. All three siblings achieved successful political careers: his older brother Kim Jonghan was a high-ranking official, and his younger brother Kim Jongheung was the magistrate of Yangju.

Career

He passed the state examination in 1405 and in 1411 he was posted as a royal inspector to Gangwon Province. In 1433, he was sent by King Sejong the Great to conquer the Manchu. Kim's military campaign captured several castles, pushed north, and restored Korean territory roughly to the present-day border between North Korea and China.^[1]

The campaigns against the Jurchens

The tribe of Wild Jurchens often crossed the Tumen and Yalu rivers and made marauding incursions through the Joseon border. Since the times of the Goryeo dynasty, there were conciliatory efforts through trade as well as attempted suppression of the raiders by force, but the border conflicts did not cease. Early in the Joseon dynasty, the northern part of Yeongbyeon county was lost to the Jurchen invaders.

To solve the issue once for all, in 1433, King Sejong sent General Choi Yun-deok to suppress the Wild Jurchens in the Yalu River Basin. In October of the same year, Kim Jong-seo led another expedition to the northern part of Hamgyeong province, where he defeated the Jurchens and strengthened the borders against future attacks.

Later life and death

Following King Sejong's death, Grand Prince Suyang's ill brother, Munjong took the throne but soon died. The crown passed to his 12-year-old son, Danjong. The new king was too young to rule the nation and all political processes were controlled by then-Chief State Councilor Hwangbo In and General Kim Jongseo. As Kim Jongseo and his faction, which included Danjong's guardian Princess Gyeonghye,^[2] used the chance to extend the power of court officials against many royal family members, the tension between Kim and Suyang greatly increased; not only Suyang himself, but his younger brother, Grand Prince Anpyeong, also sought an opportunity to take control of the kingdom.

Suyang surrounded himself with trusted allies, including his famous adviser, Han Myeong-hoe, who was the father of two queens: Queen Jangsun, the daughter-in-law of Queen Jeonghui and King Sejo, and Queen Gonghye, the daughter-in-law of Queen Insu and King Deokjong. Han was also an 8th cousin of Queen Insu. Han advised Suyang to take over the government in a coup, and in October 1453, he killed Kim Jongseo and his faction, thereby taking the reins of power into his own hands. After the coup he arrested his own brother, Anpyong, first sending him into exile, then putting him to death.

After death, he received posthumous name of Chungik in 1746 during Yeongjo's reign.^[3]