"fourth class" is also a rumor. In the Yuan Dynasty, there was only the difference between "northerners" and "southerners", and there was never any regulation to divide people into "fourth class". This rumor originated from the Historical Records of Mongols written by Tu Ji in the late Qing Dynasty and the early Republic of China. At present, the rumor of "the fourth class" in the Yuan Dynasty has been gradually deleted from the textbooks, and the original appearance of history has been restored. In the Yuan Dynasty, the "fourth class" was only different when you were an official, and it had no influence on the bottom fart people. The Mongols should go bankrupt, and they should sell themselves as slaves to the Han people. The emperor of the Yuan Dynasty repeatedly paid for the redemption of Mongolian slaves who went bankrupt and sold themselves under the Han people and Semu people, and reorganized them into military and civilian accounts. And there are no Mongolian slaves under the "Nanren". Why? This is because there are few Mongolians south of the Yangtze River! The emperor of the Yuan Dynasty prohibited Mongolians from doing business and buying houses and land south of the Yangtze River. Many rumors related to it will be broken.