On the Chosŏn Dynasty’s Legitimacy Consciousness from the Perspective of the Imperial Calendar

The orthodox calendar was a method of chronological dating. To grasp historical change, one had to measure time, and the specific methods for this were the calendar and the orthodox calendar. More than this, the orthodox calendar is also a symbol of legitimacy, and therefore rulers throughout history placed great importance on its establishment and regulation. When a new dynasty was established, its first task was to “correct the calendar and change the color of clothes.” The Records of the Grand Historian states: “When a king changes the dynastic name and receives the Mandate of Heaven, he must be cautious about the beginning, correct the first day of the month, change the color of clothes, and trace the origin of Heaven’s Yuan to follow its will.” This showed that in Chinese history, the orthodox calendar symbolized the receipt of the Mandate of Heaven, and thus no dynasty took it lightly.