The role of seals in the Chinese culture can hardly be overestimated. For the last 3,000 years they have been used in official, private, even magic spheres. The earliest examples of seals come from the Shang dynasty (BCE 16-11 c.) from the archeological sites at Anyang. However very little is known about their usage at this early stage, it is only starting from the Spring and Autumn period (BCE 722-481) that we begin to see an increased quantity of seals paired with textual references to them. According to a Han dynasty story, the first seal was given to the Yellow Emperor by a yellow dragon with a chart on its back. Another story says that it was given to Emperor Yao by a phoenix as the emperor was sitting in a boat. In any case, the receipt of the seal signifies the conferral of the Mandate of Heaven. He who has the seal possesses the Mandate of Heaven, in other words, he has been given the right to rule the empire. So when Tang, the first ruler of the Shang dynasty overthrows the last tyrant of the previous Xia dynasty, he seizes the royal seal and thus establishes his power.