First of all, we understand that history is always written by winners, and the final winner is Yuan, that is, Mongols; We need to know about the Mongols at that time. At that time, the Mongols were subordinate tribes of the Jin people, and it was arrogant for the Jin people to destroy Liao and Song. In Jin, priority is given to Jin people, just like America now. At that time, the aliens living in the Jin Dynasty lived a miserable life, especially the tribesmen. At that time, the Jin dynasty reduced the number of foreign tribes, that is, controlling the population and controlling the male members of each tribe, and reducing the number year by year. The reason is that Yuan doesn't want to admit that gold is orthodox, but Yuan's system is to inherit gold and can't completely remove its influence.

The Southern Song Dynasty fought against Mongolia at that time for 44 years, the longest among neighboring countries. It was destroyed by Yuan for more than twenty years. When the Southern Song Dynasty fought Yuan, both sides fought to the death. Yuan once played under the pressure of the Southern Song Dynasty. It was only later that Yuan changed his strategy and destroyed Dali first, thus completely surrounding the Southern Song Dynasty and forcing it to make a final decisive battle on the cliff. The Southern Song Dynasty was defeated and the world returned to Yuan Dynasty.

There were many Han Chinese who were officials in the Yuan Dynasty, and their strength was very strong. When compiling the history books of the former dynasty, there were many arguments within the Yuan Dynasty. The Yuan Dynasty inherited the Liao and Jin Dynasties in terms of system and the Song Dynasty in terms of culture. Therefore, the compilation of < Jinshi > < History of the Song Dynasty > in the Yuan Dynasty meant that all three dynasties were orthodox, but at that time, the Han people firmly disagreed. Finally, the Orthodoxy was re-compiled to confirm that the Song Dynasty was orthodox and Liao and Jin belonged to the Song Dynasty.

In the Ming Dynasty, because it was the Han Dynasty, the coexistence of the history of the Song, Liao and Jin Dynasties was unbearable, so there was a movement to rebuild the history of the Song, Liao and Jin Dynasties and respect the Song Dynasty as the orthodox system. Therefore, the orthodox position of the Song Dynasty in the Ming Dynasty is well known to the world.

In the Qing dynasty, although the Qing dynasty had this golden lineage and a criminal record that changed the history of the previous dynasty, she still admitted that she inherited the Ming dynasty and also admitted the Ming dynasty's definition of Song, Liao and Jin. The Qing dynasty did this to make itself right, not to make the Ming dynasty wrong; At the same time, tell the Han people all over the world that the Ming Dynasty was run out of luck, and I, Qing, was sent by heaven to save you instead of the Ming Dynasty.

In the definition of inheritance, although the territory of the Southern Song Dynasty is not large, you have completely inherited the humanistic system of the Northern Song Dynasty, while the Northern Song Dynasty inherited the humanistic system of the Tang Dynasty, and the Tang Dynasty inherited the Sui Dynasty, so the Southern Song Dynasty is also orthodox in the definition of inheritance.