Sejo of Joseon

Sejo of Joseon (Korean: 조선 세조, 2 November 1417 – 23 September 1468, ruled. 1455–1468) was the seventh king of the Joseon Dynasty of Korea. He was the son of King Sejong and brother of Munjong of Joseon and uncle of Danjong of Joseon, against whom he led a coup d'état to become king himself in 1455.

Sejo of Joseon
조선 세조
세조 어진 초본.jpg
King Emeritus of Joseon
Reign22 – 23 September 1468
King of Joseon
Reign25 July 1455 – 22 September 1468
PredecessorDanjong of Joseon
SuccessorYejong of Joseon
Chief State Councillor
In office11 November 1453 – 25 July 1455
PredecessorHwangbo In
SuccessorJeong In-ji
Born2 November 1417
Bon Palace, Hanseong, Kingdom of Joseon
Died23 September 1468(1468-09-23) (aged 50)
Jeongjeon, Sugang Palace, Hanseong, Kingdom of Joseon
ConsortQueen Jeonghui
Posthumous name
King Hyejang Seungcheon Chedo Yeolmun Yeongmu Jideok Yunggong Seongsin Myeongye Heumsuk Inhyo the Great
Temple name
Sejo (세조, 世祖)
HouseJeonju Yi
FatherSejong the Great
MotherQueen Soheon
Signature조선 세조의 수결.jpg
Korean name
Revised RomanizationSejo
Birth name
Revised RomanizationYi Yu
McCune–ReischauerYi Yu
Courtesy name
Revised RomanizationSuji


Early lifeEdit

Born in 1417 as Yi Yu, King Sejong the Great's second son, he showed great ability at archery, horse riding and martial arts. He was also a brilliant military commander, though he never went to the battlefront himself. He became Grand Prince Suyang (수양대군, 首陽大君) in 1428, the name by which he was better known.

Following King Sejong's death, 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 the Chief State Councillor Hwangbo In and General Kim Jongseo, who was Left State Councillor. As Kim Jongseo and his faction 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.[1]

Suyang thought that he needed to court their allies, the Ming dynasty to support his claim to the Phoenix Throne. He became an ambassador to Joseon's contemporary, Ming in 1452 in order to court Joseon's Ming allies. Suyang surrounded himself with trusted allies, including his famous adviser, Han Myeong-hoe. Han advised Suyang to take over the government in a coup, and on 10 November (10th day of the 10th lunar month) 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, Anpyeong, first sending him into exile, then sentencing him to death.[1]


Finally in 1455 he forced his powerless young nephew, Danjong, to abdicate, declaring himself seventh king of the Joseon dynasty. Later he demoted Danjong to prince and ordered him to be poisoned after his younger brother, Grand Prince Geumsung, and later six scholars including Seong Sam-mun, Pak Paeng-nyeon, and Yi Gae plotted to remove Suyang from power in an attempt to put Danjong back on the throne.

Despite having snatched the throne from his young nephew and killing many people in the process, he proved himself one of the most able rulers and administrators in Korean history. First, he strengthened the monarchy established by King Taejong by weakening the power of the State Council and bringing staff directly under the king's control. He also strengthened the administrative system, which had also been introduced by Taejong, enabling the government to determine exact population numbers and to mobilize troops effectively. Just like Taejong, he was a hardliner with regards to foreign policy and attacked the Jurchens on the northern front in 1460 (오랑캐/兀良哈) and 1467 (호리개/胡里改). He also revised the land ordinance to improve the national economy. He executed scholars from King Sejong's era (the so-called Six martyred ministers) for plotting against him, but encouraged publication of history, economics, agricultural, and religious books.

Last yearsEdit

Most importantly, he compiled the Grand Code for State Administration, which became the cornerstone of dynastic administration and provided the first form of constitutional law in a written form in Korea. He died in 1468, and the throne passed to his sickly son, Yejong.


  1. Queen Jeonghui of the Papyeong Yun clan (8 December 1418 – 6 May 1483) (정희왕후 윤씨)[2][3]
    1. Yi Jang, Crown Prince Uigyeong (1438 – 2 September 1457) (이장 의경세자)[4]
    2. Princess Uisuk (1442 – 3 December 1477) (의숙공주)[5]
    3. Unnamed princess (공주)
    4. Yi Hwang, Grand Prince Haeyang (14 January 1450 – 31 December 1469) (이황 해양대군)
    5. Yi Se-hui (이세희, 李世熺), Princess Uiryeong (의령공주) or Princess Uihwa (의화공주)[6][7][8]
  2. Royal Noble Consort Geun of the Seonsan Park clan (1425 – ?) (근빈 박씨)[9][10]
    1. Yi Seo, Prince Deokwon (6 March 1449 – 22 July 1498) (이서 덕원군)[11][12]
    2. Yi Seong, Prince Changwon (1458–1484) (이성 창원군)[13]
  3. Deposed Royal Consort So-yong of the Park clan (폐 소용 박씨) (? – 1465)[14][15]
    1. Prince Yi Aji (1459–1563) (왕자 아지)

Books compiled by SejoEdit

Sejo of Joseon compiled a number of books based on his interests. One includes Seokbosangjeol, a biography of Gautama Buddha.[16] He also created two other books:

  • Worinseokbo (Korean월인석보; Hanja月印釋譜)
  • Yeokdaebyeongyo (Korean역대병요; Hanja歷代兵要)

Depiction in arts and mediaEdit

See alsoEdit


  1. ^ a b "세조". (in Korean). Retrieved 4 February 2022.
  2. ^ Daughter of Yun Beon (윤번), Lord Jeongjeong (정정공), Internal Prince Papyeong (파평부원군); and Lady Heungnyeong, Princess Consort to the Internal Prince, of the Incheon Lee clan (흥녕부대부인 이씨)
  3. ^ Married in 1428, originally as Sejo's Grand Internal Princess Consort
  4. ^ He was first known as Prince Dowon (도원군) when his father was still Grand Prince
  5. ^ Later married Jeong Hyeon-jo (정현조), son of Jeong In-ji (정인지), Lord Munseong (문성공), and later Chief State Councillor (영의정, 11 June 1455); created Prince Consort Haseong (하성군)
  6. ^ From the unofficial history (야사 野史), accurately from the "Geumgye Pildam" (금계필담 錦溪筆談; by Seo Yoo-yeong (서유영) in 1873), but unable to confirm from the official Annals. But in 1446 (Sejong's 28th year), the Annals recorded Grand Prince Suyang (as he was still known that time) as having "1 son & 2 daughters", but there is no record or possibility of her having existed
  7. ^ The name recorded down in said unofficial history
  8. ^ She married Kim Cha-dong (김차동), the grandson of Kim Jong-seo – no issue
  9. ^ Originally of Gwi-in (귀인) rank (along with her title "Palace of Motherly Kindness and of Long Life" (자수궁 慈壽宮)), was elevated to Bin rank on 15 June 1483 (along with her title "Palace of Propriety and of Long Life" (창수궁 昌壽宮))
  10. ^ Elder sister of Park Paeng-nyeon (박팽년) (later one of the Six Martyred Ministers)
  11. ^ With his first wife, Princess Consort Imcheon of the Gyeongju Kim clan (임천군부인 경주 김씨, 林川郡夫人 慶州金氏) (1447–1481), he had two sons; Yi Jeok, Prince Yeonseong (연성군 이적,?蓮城君) (1464–1525), and Prince Deokjin (덕진군, 德津君). With his second wife, Princess Consort Bongsan of the Haman Yun clan (봉산군부인 함안 윤씨, 繼配鳳山郡夫人 咸安尹氏)(? – 12 August 1450), he had 3 sons
  12. ^ With his third wife, Princess Consort Anseong of the Cheongju Yang clan (안성군부인 청주 양씨, 配安城君夫人 淸州楊氏) (1451–1504), he had 2 sons; Yi Gam (영천도정 이감, 寧川都正) (1478–1534) and Yi Sim (동산도정 이심, 東山都正) (1489–1521). With his fourth wife, Princess Consort Changnyeong of the Changnyeong Seong clan (창녕군부인 창녕 성씨, 配昌寧郡夫人 昌寧成氏) (1453–1515), he had 3 sons; Prince Songseon (숭선군, 嵩善君) (1488–1544), an unnamed son, and Prince Cheongbu (청부군, 靑鳧君) (1494–1545)
  13. ^ With his first wife, Princess Consort Deokyang of the Gyoha No clan (덕양군부인 교하 노씨, 德陽郡夫人 交河盧氏), he had an adoptive son of his older brother; Yi Hwal, Prince Deokjin (덕진군 활, 德津君 濊). With his second wife, Princess Consort Gwangseong of the Gwangju Jeong clan (광성군부인 광주 정씨, 光城郡夫人 光州鄭氏) and his third wife, Princess Consort Han of the Cheongju Han clan (군부인 청주 한씨, 郡夫人 淸州韓氏), he had no issue.
  14. ^ Her name was Park Deok-jong (박덕중, 朴德中)
  15. ^ She was executed by hanging in the 11th year of Sejo’s reign
  16. ^ "Life History and Sermon of Buddha Abstracted from Buddhist Scriptures". World Digital Library. 1447. Retrieved 24 May 2013.
Sejo of Joseon
Born: 1417 Died: 1468
Regnal titles
Preceded by King of Joseon
25 July 1455 – 22 September 1468
Succeeded by