Joseon official and writer named an incorruptible official; pen name Cheonggang
| Life | 1536 ~ 1583 |
| Era | 조선 중기 |
| Clan | 전의 이씨 |
Yi Je-sin (李濟臣, 1536-1583) was a mid-Joseon official and writer of the Jeonui Yi clan. His courtesy name was Mongeung, his pen name Cheonggang and his posthumous name Pyeonggan. He was the great-grandson of Yi Yun-sun and grandson of Yi In-son; his father was the army commander Yi Mun-seong and his mother a daughter of U Ye-son, and he married a granddaughter of Chief State Councillor Sang Jin. The Cheonggang-gong branch that descends from him is listed as a sub-branch of the Yanggan-gong (Seo-jang) line of the Jeonseo-gong branch.
A precocious child who wrote poems from the age of seven, he is said to have impressed Nammyeong Jo Sik at first sight. At seventeen he studied under Jo Uk at Yongmunsan, and passed the classics licentiate examination in 1558 and the civil examination in 1564. He served in the Office of Royal Decrees, the National Academy and as section chief in the ministries of punishments, works and revenue; under King Seonjo he helped compile the Annals of King Myeongjong and accompanied an embassy to Ming China.
As magistrate of Ulsan from 1571 he stamped out the extortions of local clerks, and as magistrate of Jinju from 1578 he governed well until slander by local strongmen cost him his military tally and he withdrew. In 1581 he became magistrate of Ganggye and then army commander of North Hamgyeong, but when the Jurchen leader Nitanggae invaded in 1583 and took Gyeongwon, he was held responsible, exiled to Insanjin near Uiju, and died there. Exonerated in 1585, he was posthumously named Minister of War and listed as an incorruptible official, and is enshrined at Miwon Seowon in Yanggeun and Songcheon Seowon in Cheongju.
He was skilled in poetry and prose and excelled in running, cursive, seal and clerical scripts. His writings include the Cheonggang-jip, Cheonggang Soseol and Jinseong Japgi, and his anecdote collection Cheonggang Seonsaeng Hucheong Swaeeo and his poetry criticism Cheonggang Sihwa survive in the Daedong Yaseung. His great-grandsons Yi Haeng-won and Yi Haeng-jin became Right State Councillor and governor of Gyeonggi respectively.