Because they believed that since the earth was God’s crown jewel of creation, it should also be the center of the universe. Of course they were wrong, and this is a wonderful example of man following after his own will (it says explicitly in the Bible that the earth is not the center of the universe). Hope that answers your question!
It was an attempt to minimize the importance of the Mongols and to emphasize the Chinese longevity and importance. It also helped save the various scientific and social achievements that were swept aside by the Mongols.
The winning group always writes the history.
Support a large population, which eventually formed into cities
