The Son of Heaven was a title given to the Chinese ruler who was considered sacred and had power over everything under the sky. This title started with the Zhou dynasty and was based on the idea that the ruler had a mandate from heaven. Later, the title was used by other monarchs in the same region to support their own rule. The Son of Heaven was seen as the most important ruler who had power over everything. In some places, like China and Japan, the ruler was thought of as a god or a chosen one.