How did the ancient capital Nanjing prosper again after experiencing rise and fall?

At the end of the Northern Song Dynasty, Fangla from Zhejiang rebelled against the Song Dynasty and once prepared to occupy Nanjing, but it did not materialize. Soon after the Jin soldiers invaded, Emperor Gaozong of the Song Dynasty came to the throne. He accepted the suggestion of Li Gang, a member of the main war faction, and changed Jiangning Prefecture to Jiankang Prefecture as the eastern capital. Soon the Jin soldiers went south, and Gaozong fled south and temporarily stationed in Hangzhou.

In 1137, at the insistence of the main war faction Yue Fei and others, Song Gaozong went to Jiankang to serve as director. In 1138, Emperor Gaozong of the Song Dynasty fled south again to Hangzhou in the name of "cultivating virtues rather than choosing dangerous places" when establishing the capital. He officially established the capital in Hangzhou, changed Hangzhou to Lin'an Prefecture, and made Jiankang Prefecture the companion capital.

In 1275, Yuan soldiers went south and the Southern Song Dynasty was destroyed. In 1329, the Yuan Dynasty government changed Jiankang to Jiqing. The ancient capital of Nanjing has experienced ups and downs and prospered again.