Posterity of Heaven
Posterity of Heaven or Cheonson (천손, 天孫) designates the Korean people because they are considered the descendants of Heaven or the heavenly god. Based on historical records, the ancient Koreans generally worshiped the heavens and the sun, liked brightness, and considered their states governed by Heaven. Because the thought about the Posterity of Heaven, an archaic word says that "the people's mind is equal to the Heaven's mind," which warns rulers of the significance of the people. The Korean national anthem, Aegukga supports this concept. The lyrics of Aegukga say "May our nation be eternal  by the protection and help of Heaven." In addition, the National Foundation Day, Gaecheonjeol literally means the day when the sky was opened. It is natural that the sky should be opened for the Posterity of Heaven to found a nation. Title of rulers. In very ancient times, there were a divine regent who had supervised and taught the people as a representative of the Heavenly God. These divine regents were called Hwanin, Hwanung and Dangun, based on the period. Korean kingdoms had used both titles of kings and emperors as the title of rulers because they thought that the  highest rulers was Heaven, and all rulers must be a representative of Heaven. This concept of the Posterity of Heaven is somewhat different from the Chinese concept of the Son of Heaven. It is believed that the Chinese emperor governs the Chinese as the son of Heaven. But, the Koreans believe that they themselves are the descendants of Heaven, the Heavenly God governs them by himself, and a ruler of a nation is nothing but the supervisor as a representative of Heaven. Anniversary sacrifice to Heaven. Because of the Koreans' thought about Heavenly offspring, they have had an anniversary sacrifice  (month is as lunar calendar). Scholars say that dolmen in Manchuria and Korean Peninsula was an altar to sacrifice to Heaven.