He was born as
Yi Che () 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 Yangnyŏng with his third son
Prince Chungnyeong as heir apparent. 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. Yangnyŏng was unaware that Chogungjang was his uncle's woman. On 15 February 1417, Yangnyŏng secretly brought in Eori, the concubine of Gwak Seon, into the palace. Angered,
Taejong banished Yangnyŏng from the royal palace to the residence of Yangnyŏng's father-in-law, Kim Han-ro. However, Kim Han-ro arranged a rendezvous between Yangnyŏng and Eori, and Eori bore the crown prince's child. For a while,
Taejong did not fault Yangnyŏng for his libertine proclivities but instead held his father-in-law, Kim Han-ro, accountable for Crown Prince Yangnyŏng's improprieties. The final event that sealed Yangnyŏng's fate was a letter he wrote to
Taejong, accusing
Taejong of hypocrisy. Yangnyŏng criticized his father for punishing him over his affair with Eori, while
Taejong himself maintained ten concubines, in direct violation of the Confucian virtue of highest importance: filial piety. Due to Yangnyŏng's continued lack of remorse,
Taejong deposed Yangnyŏng as crown prince on 3 June 1418. Sorrowful, Taejong asked two officials who had been sent to inform Yangnyŏng of his deposition about Yangnyŏng's reaction. They reported back to Taejong that Yangnyŏng neither cried nor showed signs of sadness. Yangnyŏng was banished from the palace and relocated to
Gwangju. Taejong initially considered to create two sons of Yangnyŏng his new heir, but finally chose his own third son Grand Prince Chungnyeong, the later
Sejong. After
Sejong became king, the relationship between the brothers strengthened, with Sejong often inviting Yangnyŏng to the palace. During
Sejo's reign, Yangnyŏng enjoyed the status of the eldest royal family member, and Sejo often invited Yangnyŏng to the palace for court revelries. Yangnyŏng died in 1462, the eighth year of
Sejo's reign, at the age of 68. The tomb of Prince Yangnyŏng reopened in 2018 to the public after 18 years of closure. ==Family==