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Yi Seon 이선
A 19th century portrait of Sado
Regent of Joseon
Tenure	11 March 1749 – 4 July 1762
Predecessor	Crown Prince Yi Geum
Successor	Grand Heir Yi San
Monarch	Yeongjo of Joseon
Crown Prince of Joseon
Tenure	25 April 1736 – 4 July 1762
Investiture	Injeongjeon Hall, Changdeokgung, Hansŏng, Joseon
Predecessor	Crown Prince Yi Haeng
Successor	Crown Prince Yi Sun
Born	13 February 1735 Jibbokheon Hall, Changgyeonggung, Hansŏng, Joseon
Died	12 July 1762 (1762-07-13) (aged 27) Munjeongjeon Hall, Changgyeonggung, Hansŏng, Joseon
Burial	Yungneung Tombs, Yunggeonneung Cluster, Hwaseong, Gyeonggi Province, South Korea
Consort	Lady Hyegyŏng (m.1744–1762)
Issue	Yi San, King Jeongjo of Joseon
Posthumous name Joseon: Crown Prince Sado → Crown Prince Jangheon → King Sinmun Hwanmu Jangheon Gwanghyo the Great 사도세자 → 장헌세자 → 신문환무장헌광효대왕 莊獻世子 → 思悼世子 → 神文桓武莊獻廣孝大王 Korean Empire: Emperor Sinmun Hwanmu Jangheon Gwanghyo Ui 신문환무장헌광효의황제 文桓武莊獻廣孝懿皇帝 Temple name Jangjong (장종; 莊宗) → Jangjo (장조; 莊祖)
Clan	Jeonju Yi clan
Dynasty	House of Yi
Father	Yeongjo of Joseon
Mother	Royal Noble Consort Yeong (biological) Queen Jeongseong (adoptive)
Religion	Neo-Confucianism

Crown Prince Sado (Korean: 사도세자; Hanja: 思悼 世子; 13 February 1735 – 12 July 1762), personal name Yi Seon (이선; 李愃), was the second son of King Yeongjo of Joseon. His biological mother was Royal Noble Consort Yeong of the Jeonui Yi clan. Due to the prior death of Sado's older half-brother, Crown Prince Hyojang, the new prince was the probable future monarch. However, at the age of 27, he died, most likely of dehydration and possibly of starvation after being confined in a rice chest on the orders of his father in the heat of summer.^[1]

Lady Hyegyŏng, Sado's wife, wrote a memoir in 1805 detailing their life together. She records that the prince suffered a severe illness in 1745, during which he often lost consciousness.^[2] Although he recovered, the tense relationship between Sado and his father King Yeongjo led to him experiencing severe anxiety whenever in his father's presence.^[3] When Sado came of age at 15, his father appointed him regent, giving him the power to make decisions on administrative matters.^[4] Yeongjo wanted Sado to have an experience of ruling the country. At the same time, Yeongjo wanted stronger power. During Sado's regency, the dispute between Soron and Noron became stronger, much to Yeongjo's disappointment.^[5] Lady Hyegyŏng describes King Yeongjo as perpetually dissatisfied with whichever course of action Sado chose.^[6] Yeongjo also did not permit Sado to visit the ancestral tombs until as late as 1756, nor was he allowed to attend auspicious court events.^[7] Yeongjo also always made sure to chastise his son in front of a large crowd, either of ladies-in-waiting or eunuchs.^[8] As a result, Sado formed a strong bond with his sister Princess Hwahyeop, who was similarly disfavoured by their father. When she died in 1752, Sado was reported to have grieved intensely.^[9]

In 1752, Sado read a Taoist text called Okchugyeong (옥추경; 玉樞經). Whilst reading, he hallucinated that he saw the Thunder God. Henceforth, he was terrified of thunder and refused to touch any object engraved with the characters of the book.^[10]

Sado took a secondary consort, Yang-je (Royal Noble Consort Suk), with whom he had a son in 1754. Terrified of his father's anger, Sado forced her to take abortive medicines, but still, the child was born safely. Arrangements for the delivery and housing were made by Lady Hyegyŏng.^[11]

In 1757, King Yeongjo's adoptive mother (Queen Inwon) and wife (Queen Jeongseong) died within a month of each other. Sado had been close to both of them and their deaths led to a marked deterioration in his mental health and relationship with his father.^[12] As a way of dealing with his frustration and rage, Sado beat his eunuchs.^[8] In the same month as the burial of Queen Jeongseong, Sado walked into his chambers holding the severed head of a eunuch whom he had killed, forcing the ladies-in-waiting and his wife to view it. After this, he frequently killed palace staff to release his emotions,^[13] as well as assaulting and raping many ladies-in-waiting.^[13] Lady Hyegyŏng reported Sado's issues to his mother Royal Noble Consort Yeong, but begged her not to speak to anyone about the matter, as she feared for her safety if Sado discovered she had told someone.^[13] By 1758, a previous phobia of Sado's regarding clothing (vestiphobia) became intensely problematic.

For him to get dressed, I had to have ten, twenty, or even thirty sets of clothes laid out. He would then burn some, supposedly on behalf of some ghost or other. Even after this, if he managed to get into a suit of clothes without incident, one had to count it as great good luck. If, however, those serving him were to make the slightest error, he would not be able to put his clothes on, no matter how hard he tried. In the process, people were hurt, even killed. It was truly dreadful.

— Lady Hyegyŏng, ^[14]

Late in 1757, Sado took another secondary consort, Park Bing-ae (Royal Noble Consort Gyeong), who had been a lady-in-waiting to his grandmother, so his relations with her were considered to breach the incest taboo.^[15] When Yeongjo found out, he berated his son and Sado eventually jumped down a well to attempt drowning himself, but a guard pulled him out. Lady Hyegyŏng had, by this point, managed to have Bing-ae hidden in the home of Sado's sister, Princess Hwawan.^[16]

On his birthday in 1760, Sado suffered a burst of outrage at his parents, berating his mother Lady Yeong-bin, as well his own son, and two daughters.^[17] After this, he demanded that Princess Hwawan use her influence over King Yeongjo to move palaces and allow Sado to visit the springs at Onyang.^[18] He also threatened to "slash Princess Hwawan with [his] sword", an event witnessed by Lady Hyegyŏng and Lady Yeong-bin.^[19] While Lady Hyegyŏng said he was not violent to her, she also noted he would beat any women who resisted his sexual overtures until he "rent their flesh" and they gave in. There was one documented incident where Sado was physically violent toward his wife, in which he threw a go board at her face and made it necessary for Lady Hyegyŏng to avoid court events to hide the bruises.^[20]

In 1761 Sado beat his secondary consort Bing-ae, who had birthed several of his children, in a fit of rage while getting dressed. He left her on the floor, where she died of her injuries. Lady Hyegyŏng prepared her body for the funeral rites, but, on his return, Sado reportedly said nothing about Bing-ae's death.^[21]

In the summer of 1762, an altercation with an official at court enraged Sado. In revenge, he threatened to kill the official's son,^[22] and attempted to sneak through a water passage to the upper palace. He failed to find the son and, instead, confiscated clothing and items belonging to him. Rumours that Sado had attempted to enter the upper palace to kill King Yeongjo spread around the court.^[23] Fearing for the safety of her grandchildren, Royal Consort Yeong begged Yeongjo to deal with Sado.^[24] By court rules, the body of a royal could not be defiled and, under the then-common practice of communal punishment, Sado's wife and son (the family's only direct male heir) could also face death or banishment if he were executed as a criminal and traitor.^[25] As a solution, Yeongjo ordered Sado to climb into a wooden rice chest (roughly 1.3m square / 4 feet square) on a hot July day in 1762.^[26] According to Lady Hyegyŏng's memoirs, Sado begged for his life before getting into the chest, though he attempted to get out again.^[27]

Along with her children, Lady Hyegyŏng was taken back to her father's house on the same day. After two days, King Yeongjo had the chest containing Sado tied with rope, covered with grass, and moved to the upper palace.^[28] Sado responded from inside the chest until the night of the seventh day; the chest was opened and he was pronounced dead on the eighth day.^[29] Yeongjo then restored him to the position of crown prince and gave him the posthumous title Sado, meaning "thinking of with great sorrow".^[30]

During the 19th century, there were rumours that Prince Sado had not been mentally ill, but had been framed; however, these rumours are contradicted by his wife, Lady Hyegyŏng, in The Memoirs of Lady Hyegyŏng. According to historians, there is no evidence that Sado was the victim of a conspiracy.^[31]

Crown Prince Sado was buried on Mt. BaebongSan in Yangju. His body was moved by his son, King Jeongjo, to its current location in 1789, then called Hyeonnyungwon near Suwon, 30 kilometres south of Seoul. Five years later the Hwaseong Fortress was built by King Jeongjo, specifically to memorialize and honour his father's tomb (the construction lasted from 1794 to 1796, while the official reception was 1795). Lady Hyegyŏng died and was buried with her husband in 1816.

Prince Sado and Lady Hyegyŏng were posthumously elevated in status and given the titles Emperor Yangjo and Empress Heonyeong in 1899 during the reign of Emperor Gwangmu (Gojong). Their tomb and the adjacent tomb of their son, King Jeongjo, and his wife, Queen Hyoui, were upgraded accordingly and renamed Yungneung.

Prince Sado was reinstated fifteen days after he died but King Yeongjo banned any mention of the prince's name for the rest of his reign. Because of this decision, Prince Sado's son, Jeongjo, ascended the throne following the passing of King Yeongjo as the heir to his deceased half-uncle (Crown Prince Hyojang). Upon becoming king, however, one of Jeongjo's first statements was to declare, "I am the son of Prince Sado."^[32] Jeongjo always showed great filial devotion to his father, Crown Prince Sado, and he changed the posthumous name of his father's to a longer one, which is the origin of the latter's alternative title, Crown Prince Jangheon.

• Father: King Yeongjo of Joseon (조선 영조; 31 October 1694 – 22 April 1776)
  • Grandfather: King Sukjong of Joseon (조선 숙종; 7 October 1661 – 12 July 1720)
  • Biological grandmother: Royal Noble Consort Suk of the Haeju Choe clan (숙빈 최씨; 17 December 1670 – 9 April 1718)
  • Adoptive grandmother: Queen Inwon the Gyeongju Kim clan (인원왕후 김씨; 3 November 1687 – 13 May 1757)
• Biological mother: Royal Noble Consort Yeong of the Jeonui Yi clan (영빈 이씨; 15 August 1696 – 23 August 1764)
  • Grandfather: Yi Yu-beon (이유번; 1670–?)
  • Grandmother: Lady Kim of the Hanyang Kim clan (한양 김씨; 1670–?)
• Adoptive mother: Queen Jeongseong of the Daegu Seo clan (정성왕후 서씨; 12 January 1693 – 3 April 1757)

Consorts and their Respective Issue(s):

1. Queen Heongyeong of the Pungsan Hong clan (헌경왕후 홍씨; 6 August 1735 – 13 January 1816)
   1. Yi Jeong, Crown Prince Uiso (의소세자 이정; 27 September 1750 – 17 April 1752), first son
   2. Grand Heir Yi San (왕세손 이산; 28 October 1752 – 18 August 1800), second son
   3. Royal Princess Cheongyeon (청연공주; 1754 – 9 June 1821), first daughter
   4. Royal Princess Cheongseon (청선공주; 1756 – 20 July 1802), second daughter
2. Royal Noble Consort Suk of the Buan Im clan (숙빈 임씨; 1732–1773)
   1. Yi In, Prince Euneon (은언군 이인; 1 February 1754 – 30 June 1801), third son
   2. Yi Jin, Prince Eunsin (은신군 이진; 1755–1771), fourth son
3. Royal Noble Consort Gyeong of the Park clan (경빈 박씨; 1735–1761)
   1. Princess Cheonggeun (청근옹주; 1758–1835), third daughter
   2. Yi Chan, Prince Eunjeon (은전군 이찬; 14 August 1759 – 26 August 1778), fifth son
4. Court Lady Yi (수칙 이씨; 守則 李氏)
5. Ga-seon (가선; 假仙; 1735–1762)

• Portrayed by Hwang Hae-nam in the 1956 film The Tragic Prince.
• Portrayed by Do Kum-bo in the 1963 film Mangbuseok (A Wife Turned to Stone).
• Portrayed by Jeong Bo-seok in the 1988 TV series O, Heaven.
• Portrayed by Choi Soo-jong in the 1988 MBC TV series 500 Years of Joseon: The Memoirs of Lady Hyegyeong.
• Portrayed by Im Ho in the 1998 MBC TV series The Great King's Road.
• Portrayed by Lee Chang-hoon in the 2007 MBC TV series Lee San, Wind of the Palace.
• Portrayed by Jo Han-jun in the 2007 CGV TV series Eight Days, Assassination Attempts against King Jeongjo.
• Portrayed by ?? in the 2008 KBS2 TV series The Great King, Sejong.
• Portrayed by Oh Man-seok in the 2011 SBS TV series Warrior Baek Dong-soo.
• Portrayed by Lee Je-hoon in the 2014 SBS TV series Secret Door.
• Portrayed by Yoo Ah-in in the 2015 film The Throne.^[33]
• Portrayed by Do Sang-woo in the 2021 MBC TV series The Red Sleeve.^[34]
• Portrayed in a fictitious manner in the webcomic "Vampire of the East" by Joohee Jo and Seunghee Han published by NETCOMICS
• A fictionalized version of the prince appears in the novel The Red Palace by June Hur

• Kim Haboush, JaHyun (2013). The Memoirs of Lady Hyegyŏng: The Autobiographical Writings of a Crown Princess of Eighteenth-Century Korea (2 ed.). Berkeley: University of California Press. ISBN 978-0-520-20055-5.

• Biography of Crown Prince Sado of Korea