nephew of Seong Dam su (성담수) and Seong Dam-nyun (성담년). One of the members of Saengyukshin (생육신), and first cousin once removed of Seong Sam-mun (성삼문). He was one of the members of Sayukshin. He was grand uncle of Yulgok Yi I (율곡 이이). Prime minister of Joseon Dynastys 1549 to 1551.