Imperial titles were used in various historical Korean states before the 14th century and at the turn of the 20th century: Early Korean states used "great king", "greatest king", and "holy king"; later Korean states used "emperor". Korean monarchs who used imperial titles had political and religious authority over a realm or domain. The Chinese concept of tianxia, pronounced "cheonha" in Korean, was variously adopted and adapted to Korean views of the world from period to period.
Three Kingdoms of Korea
The 5th century was a period of great interaction on the Korean Peninsula that marked the first step toward the unification of the Three Kingdoms of Korea. The earliest known tianxia view of the world in Korean history is recorded in Goguryeo epigraphs dating to this period.
Dongmyeong of Goguryeo was a god-king, the Son of Heaven, and his kingdom was the center of the world. As the descendants of the Son of Heaven, the kings of Goguryeo were the Scions of Heaven (), who had supreme authority and sacerdotally intermediated between Heaven and Earth. The Goguryeo concept of tianxia was significantly influenced by the original Chinese concept, but its foundation laid in Dongmyeong. In contrast to the Chinese tianxia, which was based on the Mandate of Heaven, the Goguryeo tianxia was based on divine ancestry. As Goguryeo became centralized, Dongmyeong became the state god of Goguryeo. His worship was widespread among the people, and the view that Goguryeo was the center of the world was not limited to the royal family and aristocracy. Dongmyeong was worshiped well into the Goryeo period of Korea; Yi Gyubo said "Even unlettered country folk can tell the tale of King [Dongmyeong]."
Goguryeo was an authority unto itself. It had an independent sphere of influence in Northeast Asia for more than 200 years around the 5th and 6th centuries. Goguryeo viewed itself as the Land of the Scion of Heaven and viewed its neighboring states of Baekje, Silla, and Eastern Buyeo as tributary states. Together, they constituted a Goguryeo tianxia. A strong sense of commonality emerged, later culminating in a "Samhan" consciousness among the peoples of the Three Kingdoms. The Three Kingdoms of Korea were collectively called the Samhan in the Sui and Tang dynasties. Earlier, Goguryeo was called Samhan in the Book of Wei. The unification of the Samhan was later proclaimed by Silla in the 7th century and Goryeo in the 10th century.
Goguryeo monarchs were called kings, not emperors. Goguryeo kings were sometimes elevated to "great kings", "holy kings", or "greatest kings". They were equivalent to emperors and khagans. The Goguryeo title of "greatest king", or taewang (), was similar to the Chinese title of "heavenly king". "King" was first used in Goguryeo around the beginning of the Common Era; it was first used in Northeast Asia in the 4th century BCE in Old Joseon, before "emperor", or huangdi, was first used in China. The indigenous titles of ga, gan, and han, which were similar to khan, were downgraded and the sinified title of king, or wang, became the supreme title in Northeast Asia. Goguryeo monarchs being called kings was not in deference to China; wang was not inferior to huangdi or khan in Goguryeo tradition.
Goguryeo had a pluralistic concept of tianxia. The Goguryeo tianxia was one among others that constituted the world. During the 5th and 6th centuries, a balance of power was maintained in East Asia between the Northern and Southern dynasties, the Rouran Khaganate, Goguryeo, and, later, Tuyuhun. Goguryeo maintained tributary relations with the Northern and Southern dynasties; the relationships were voluntary and profitable. A policy of coexistence was pursued and relations were peaceful. Goguryeo's tributary relations with the Northern and Southern dynasties were nominal. The Northern and Southern dynasties had no control over Goguryeo's foreign policy; Goguryeo pursued policies that went against Chinese interests. Goguryeo restrained Northern Wei, the strongest power in East Asia at the time, by allying with its enemies. Northern Wei said that Goguryeo was "worthy" and gave preferential treatment to its envoys. Southern Qi said that Goguryeo was "so strong that it [would not] follow orders". Goguryeo maintained cordial relations with the Rouran, and together attacked the Didouyu.