Founding, Jeongsa and Jwamyeong merit subject of Joseon; founder of the Yangjeol-gong branch
| Life | 1347 ~ 1417 |
| Era | 고려 말~조선 초 |
| Clan | 한양 조씨 |
Jo On (趙溫, 1347-1417) was an official of late Goryeo and early Joseon of the Hanyang Jo clan, with the posthumous title Yangjeol (良節). His grandfather was Lord Yongseong Jo Don and his father Prince Yongwon Jo In-byeok; the Encyclopedia of Korean Culture gives his mother as a lady of the Hadong Jeong clan. Because his stepmother Princess Jeonghwa was King Taejo's sister, he is said to have served Yi Seong-gye devotedly as his uncle from childhood.
He joined the Wihwa Island withdrawal of 1388 as Minister of Personnel and became one of its merit subjects; in 1392 he helped raise Yi Seong-gye to the throne, becoming a second-rank founding merit subject, governor of Pyongyang and Lord Hancheon. In 1393, as Northwest Commissioner, he defeated Japanese pirates at Suju and enrolled able-bodied men of Uiju in the military registers. In the First Strife of Princes in 1398 he aided Yi Bang-won as commander of the royal guard and became a Jeongsa merit subject, and in the Second Strife of 1400 he helped put down Yi Bang-gan. That year the retired king had him exiled to Wansan for the killing of Jeong Do-jeon and others, but he was released that same day, together with Yi Mu and Jo Yeong-mu who had received the same order, at the request of the censors and ministers.
When Taejong took the throne in 1401 he became a Jwamyeong merit subject and Prince, and travelled to Ming as birthday envoy. In 1402 he served as Chanseongsa of the State Council and Inspector of the Northeast. He was noted for filial piety, integrity and frugality. Of his sons Jo Ui, Jo Wan, Jo Ha, Jo Heung and Jo Yuk, the descendants of four formed the Hanpung-gun, Doje-gong, Champan-gong and Gosa-gong branches, together the Yangjeol-gong line. His daughters married Yi Jung-gyeong, Yun Hui-jeon and Yi So-in. His career is recorded in the annals of Taejo, Jeongjong and Taejong and in the Gukjo Inmulgo. Jeongam Jo Gwang-jo, leader of the Sarim under King Jungjong, was his great-great-grandson.