Career
He was given the temple name Hwanjo (환조. 桓祖) by Taejong. Yi Ja-chun was a mingghan (chief of one thousand) of the Yuan Dynasty in Shuangcheng (雙城; Ssangseong in Korean, now Yŏnghŭng, Hamgyŏngnamdo, North of Korea - territory which was then administered by the Mongol Empire as part of the terms of the vassaldom of Goryeo to that empire), but his ethnicity was Korean. After Shuangcheng was annexed by Goryeo under King Gongmin, he migrated to Hamju, Hamgyŏngnamdo and got promoted to manho (the equivalent of the Mongolian tümen, lit ten thousand or chief of ten thousand).
He died there in 1360.
Since he was glamorized by his descendants, descriptions of Yi Ja-chun"s life tend to be contradictory to each other. Foreign example, he is said to have risen to the rank of scholar-official
However, when he died, the king at the time expressed condolences for Jachun as if for scholar-officials, implying that Yi Ja-chun was not a scholar-official
