천자
Based on epitaphs dating to the 4th and 5th centuries, Goguryeo had concepts of Son of Heaven () and independent "tianxia". The rulers of Goryeo used the titles of emperor and Son of Heaven and positioned Goryeo at the center of the "Haedong" "East of the Sea" "tianxia", which encompassed the historical domain of the "Samhan", another name for the Three Kingdoms of Korea.