Historical problems in the pre-Qin period

Agree with upstairs, mainly through oral folklore.

Of course, it does not rule out that some people collected and sorted out these histories in the pre-Qin period, and even wrote books, so Zuo Shi and Confucius were very familiar with them and even admired them. However, by the time of Qin Shihuang, the rule of Legalism had been established, and Ying Zheng himself was very disgusted with the retro king of corrupt scholars, so he deliberately destroyed these history books in the process of burning books and burying Confucianism. In Sima Qian's time, we can only rewrite the history of three generations through his own investigation and collection of legends.