This family register is a document about Yi Seong-gye, drawn up at the local government office in Yeongheung, the birthplace of Yi [later King Taejo (1335-1408; founder of the Joseon Dynasty)]. People of the noble family were required to renew their family register every three years. A copy was kept at the local government office, and the other copy was kept by the people. This one appears to be the one kept by Yi Seong-gye. The family register keeps information such as his official position, feudal estate allocated to him, names of his brothers, children (including Yi Bang-won, the third king of the Joseon Dynasty), sons-in-law, and slaves. The family register is a very important material about Yi Seong-gye and his family as well as the family register system of that era.