Grand Prince Jeongwon (Hanja: 定遠大君; Born: June 22nd, 1580 - Died: December 29th, 1619) was the fifth son of King Seonjo, 14th Monarch of Joseon Dynasty and younger stepbrother of King Gwanghae, 15th Monarch of Joseon Dynasty. He was conferred the posthumous title of Daewongun (Father of King) when his son came to the throne in a coup to become King Injo, and in 1632 he was invested as posthumous king. As the good-looking, prudent Prince Jeongwon was a filial son and on good terms with his brothers, he was beloved by his father. He was designated as a vassal of merit for escorting King Seonjo when he took refuge in Uiju during Japanese Imjin Invasion (1592~1598).
He had deep respect for his parents and a strong affection for his siblings. Grand Prince Jeongwon’s third son, Grand Prince Neungchang (능창대군/綾昌大君) was exiled to Ganghwa Island (present-day Ganghwa County, Incheon Metropole), under a false accusation and ended up committing suicide. Grand Prince Jeongwon was shocked at the tragic death of his son and died in 1619.
Grand Prince Jeongwon and his consort, Lady Gyeun of Neungseong Gu Clan were buried at Geumgok-dong, Namyangju, Gyeonggi Province. In 1627, these tombs were moved to the present location at Gimpo, Gyeonggi Province (Specific Location: 79 Jangneung Avenue/Jangneungno, Pungmu-dong san 141-1 beonji, Gimpo City, Gyeonggi Province) which is known as Royal Tomb of Jangneung at Gimpo (Hangul: 김포장릉).
Grand Prince Jeongwon and Lady Gyeun were promoted into posthumous King Wonjong and Queen Inheon of Neungseong Gu Clan respectively in 1632. He was posthumously known as King Wonjong Gongnyang Gyeongdeok Inheon Jeongmok Janghyo the Great (원종공량경덕인헌정목장효대왕/恭良敬德仁憲靖穆章孝大王).