1. Wei, Jin, Southern and Northern Dynasties first developed in southern China.
Before Wei and Jin Dynasties, the political center of China was always in the north, so the development of the north was once very prosperous, and the south is now called "the land of barbarians". Until the Wei, Jin, Southern and Northern Dynasties, the northern turmoil, and civilians moved south, the south was first developed. Since then, this virgin land in the south has been full of vitality.
2. During the Anshi Rebellion, the South began to develop by leaps and bounds.
During the Anshi Rebellion, the Tang Dynasty turned from prosperity to decline, and the north was once again in turmoil. However, the unrest came suddenly, causing a large number of civilians to move south. For the first time, the south has changed from a vast land with few people to a narrow land with dense people.
3. In the Southern Song Dynasty, the South finally became a land of wealth.
Song Dynasty (the first civilian politics, which never killed a scholar, was called the "best" era by scholars) was weak but not poor. However, it is precisely because of "weakness" that "it is difficult to get better". However, it is precisely because of this turmoil that the South finally became a "land of wealth".