The first purpose is to leave real historical materials for future generations. Historical figures and events need to be recorded before they can be handed down in the form of words, and future generations can learn the real historical situation thousands of years ago from these historical documents. This is a great book, and such a historian deserves respect. Generally speaking, every dynasty has historians who are responsible for compiling historical documents, such as Sima Qian and Ban Gu, all of whom are famous historians. These people compile historical materials for the government and record relatively real historical situations.

The second purpose is to write history for the specific purpose of the rulers. This situation was very common in feudal times. After the demise of a dynasty, in order to reflect the legitimacy and superiority of its dominant position, the subsequent dynasties often publicized the superiority of their own dynasties and discredited some people and things in the previous dynasty when compiling historical materials. This kind of historian writes history for a specific purpose, in fact, it is ghostwriting for the ruling class. It is also for this reason that some situations in the ancient historical documents we see now are not true.

The third kind is people who write about unofficial history. They are trying to record some historical materials that the government is not allowed to write. This situation was also common in ancient times. There must be some historical events in each dynasty that are inconvenient to write in detail. After all, historians need to consider various influences when writing history, such as? Song Taizu's death? Of course, it is impossible to record this event in great detail in the historical materials of the Song Dynasty, but various possibilities will be analyzed in some unofficial history. There is also a famous Wild Harvest in Wanli, which also records a lot of information about unofficial history.

Although this kind of information on unofficial history is not compiled by the government, its existence value cannot be denied blindly. Some unofficial history documents are compiled by the author according to his personal experience, and these materials are of high historical value, which can make up for the lack of official historical documents. Of course, not all unofficial history can be trusted. Some unofficial history materials are written by the author through hearsay, and their objectivity will be compromised.