The Yuan Dynasty was the first dynasty established by ethnic minorities in history, but it was mainly Mongolian. After they settled in the Central Plains, the population of the Yuan Dynasty was greatly reduced due to ethnic differences and Mongolian ignorance of planting in the Central Plains.
Let's take a concrete look at these reasons:
The first reason is that the Mongols have adopted a cruel way of killing the rebellious Central Plains people. According to historical records, at the beginning of Yuan Dynasty, about 70 million people died because of the massacre of Mongolian army. At that time, the most fierce resistance to Mongolia was Sichuan, so the massacre in Sichuan was the most cruel place, and the population decreased from13 million to 600,000. It is no exaggeration to call this behavior a massacre.
The second reason is that diseases and plagues were rampant in the Yuan Dynasty, when Mongols were not proficient in medical skills, resulting in a very serious death. Historians speculate that the plague brought by Mongols from the northern grasslands may have caused a large number of people in the Central Plains to be infected. The third reason is that the natural disasters in the Yuan Dynasty were very serious. I think Mongolians are mainly nomadic people. They don't know how to farm fields and control floods.
The fourth reason is that many southerners have fled to Nanyang to live because of people's migration and refuge.
In this way, the population dropped sharply after the establishment of the Yuan Dynasty, and the people lived in dire straits at the beginning of the establishment.