경기고등학교
After the World War II, a series of nobility titles within Japan were abolished, including "kazoku" and Korean nobles, Yi Cheong lost his title in 1947 became a commoner ever since; around the same time, the Republic of Korea was founded. A law was legislated regarding the property of the former Imperial family and many of which was confiscated, but after the negotiation by Park Chan-ju, Yi Cheong and his family were allowed to own Unhyeongung, which was returned in 1948, based on the fact that the origin of Unhyeongung was the private residence of Heungseon Daewongun and his family. Under their procession, nevertheless, the scale of current Unhyeongung is much smaller than it used to be, because parts of the land were sold in decades, for various reasons including debt settlement and road expansion. During the tenure of President Syngman Rhee in 1950s, since Yi Cheong and Rhee are both from the Jeonju Yi clan and the latter was childless, Rhee asked to adopt Yi Cheong after they met, but this proposal was refused by the family of Unhyeongung. In 1954, Yi Cheong went to Kyunggi High School and later, in 1960, he acquired the decree from the Department of Civil Engineering of Marquette University, United States. On December 25, 1966, Yi Cheong's younger brother, Yi Jong, passed away in a traffic accident during his study career in the United States, making Yi Cheong the only remaining issue of his family.