Since the 8th Century B.C., two sets of legends about the Five Emperors of Ancient China had emerged. One of them was mythology-related. The Five Emperors-Tai Hao (太昊 ), Shao Hao (少昊 ), Huang Di (黃帝 ), Yan Di (炎帝 ) and Zhuan Xu (顓頊 )-were each in charge of the running of the five planets of Mercury, Mars, Jupiter, Venus and Saturn; the five directions including east, south, west, north and central as well as the changes of the four seasons of spring, summer, autumn and winter. As a matter of fact, the legend of the Five Emperors did, to a certain extent, reflected the scientific knowledge of the Ancient Chinese. The scientific connotations of the legend of the Five Emperors were firstly, the ancient people's knowledge of astronomy and meteorology. Secondly, animals were classified into five main groups. Thirdly, that the tools used by the Five Emperors to govern Heaven and Earth were simply those used by ordinary people showed that the Chinese were practical. Finally, that the daily activities of human beings in the four seasons were severely restricted was in keeping with the idea of long-term environmental protection.