This custom could be traced back to the Zhou Dynasty (1046 - 256 BC) and was more often practiced by the royal class on the Autumnal Equinox. At that time, the custom had no festival background at all. Later in the Sui (581 - 618 AD) and Tang (618 - 907 AD) dynasties, social prosperity inspired the custom of appreciating the moon on the moon sacrifice ceremony day among common people and the two merged. The people expressed their faith more liberally than the royal class and so they did not strictly hold their activities on the Autumnal Equinox