It is generally believed that Chinese civilization has two direct sources, namely, the Yellow River civilization and the Yangtze River civilization. Chinese civilization is mainly the result of the exchange and sublimation of these two regional civilizations.
Some historians believe that in the history of human civilization, the definition of "historical era" is calculated from the time when words were produced, and the previous period is called "prehistoric era". Prehistoric times: there were Chao, Sui, Fu, Shennong (Emperor Yan) and Huangdi (Xuanyuan)? Be honored as the humanistic ancestor of the Chinese nation.