| Yi Je 이제 | |
| Succession: | Crown Prince of Joseon |
| Reign: | 6 August 1404 – 3 June 1418[1] |
| Reign-Type: | Tenure |
| Spouse: | Princess Consort Suseong of the Gwangsan Kim clan |
| Spouse-Type: | Wife |
| Dynasty: | House of Yi |
| House: | Jeonju Yi clan |
| House-Type: | Clan |
| Father: | Taejong of Joseon |
| Mother: | Queen Wongyeong of the Yeoheung Min clan |
| Religion: | Neo-confucianism |
| Predecessor: | Crown Prince Yi Bang-won |
| Successor: | Crown Prince Yi Do |
| Birth Date: | 1394 |
| Birth Place: | Hanseong, Joseon |
| Place Of Burial: | Sangdo-dong, Dongjak District, Seoul, South Korea |
| Hangul: | 양녕대군 |
| Rr: | Yangnyeong Daegun |
| Mr: | Yangnyŏng Taegun |
| Hangulborn: | 이제 |
| Rrborn: | Yi Je |
| Mrborn: | Yi Che |
| Hangulja: | 후백 |
| Rrja: | Hubaek |
| Mrja: | Hubaek |
| Hangulph: | 강정 |
| Rrph: | Gangjeong |
| Mrph: | Kangjŏng |
Grand Prince Yangnyeong (; 1394 – 8 October 1462[2]) was the former Crown Prince of the Korean Joseon Dynasty. He was the first son of King Taejong and his wife, Queen Wongyeong. Yangnyeong was the elder brother of Sejong the Great, and an ancestor of Syngman Rhee, an independence activist and the first President of South Korea.
He was born as Yi Je in 1394. Originally his father appointed him as crown prince but he eventually executed Queen Wongyeong's brothers and in the 18th year of his reign replaced Prince Yangnyeong with his third son Prince Chungnyeong as heir apparent.[3] Known for his literature and calligraphy skills, the former crown prince lacked in the requisite skills for kingship and acted extremely rude in court. On May 1415, he caused a scandal when he had an affair with Chogungjang, the kisaeng of his uncle and former king, Jeongjong. Yangnyeong was unaware that Chogungjang was his uncle's woman.[4] On 15 February 1417, Yangnyeong secretly brought in Eori, the concubine of Gwak Seon, into the palace. Angered, Taejong banished Yangnyeong from the royal palace to the residence of Yangnyeong's father-in-law, Kim Han-ro. However, Kim Han-ro arranged a rendezvous between Yangnyeong and Eori, and Eori bore the crown prince's child.[5] For a while, Taejong did not fault Yangnyeong for his libertine proclivities but instead held his father-in-law, Kim Han-ro, accountable for Crown Prince Yangnyeong's improprieties.[6]
The final straw that sealed Yangnyeong's fate was a letter he wrote to Taejong, accusing Taejong of hypocrisy for punishing him over his affair with Eori, despite Taejong himself having ten concubines, in direct defiance of the Confucian virtue of the highest importance: filial piety.[7] Due to Yangnyeong's behavior showing no signs of penitance, Taejong deposed Yangnyeong from his position as crown prince on 3 June 1418.[8] The Veritable Records describe a scene in which Taejong asks two officials who were sent to apprise Yangnyeong of his deposition. They report back to Taejong that Yangnyeong did not cry and showed no signs of sadness.[9] Grand Prince Hyoryeong, Yangnyeong's second brother, had similar feelings about Chungyeong being king, and so he became a monk in a Buddhist temple. Yangnyeong was banished from the palace and relocated to Gwangju.
After Sejong had taken the throne, the relationship between the brothers strengthened, and Sejong often invited Yangnyeong to the palace. Yangnyeong enjoyed the status of the eldest royal family member during Sejo's reign, and Sejo often invited Yangnyeong to the palace for court revelries.
Yangnyeong died in 1462, the eighth year of Sejo's reign, at the age of 68.[10]
The tomb of Prince Yangnyeong reopened in 2018 to the public after 18 years of closure.[11]