李珥
The founder of this clan was Yi Dongsu, an official of the Goryeo period. This was a prominent yangban clan during the Joseon Dynasty, producing figures including the admiral Yi Sun-sin and the philosopher Yi I. The clan seat, Deoksu, corresponds to Deoksu-"hyeon", an old division of what is now Kaep'ung-gun in Kaesong city, North Korea.