Originally Deoksugung Palace was the home of king Seongjong's older brother. But when the Japanese invaded Joseon in the 16th century all the palaces burned down. So king Seonjo moved in to Gyeongung to live. But when the war was done, king Gwanghae moved in to a new palace. But king Gojong came in again to Gyeongung so they changed the name in to Deoksugung. Because wherever the king lives its name has to be '~gung' so it became Deoksugung.