Strong contact with outside countries is established and trade flourishes. Efficient governing system is developed that lasts for centuries. China splits into independent states and the Great Wall is expanded. Northern Song states enter warring period, Southern Song states remain peaceful. Mongols invade north and later under Genghis Khan Beijing is established as capital.
Paper money is used and tea becomes popular throughout China.
In 1250, census 108 million. Native Chinese re-establish rule and set up new government structures. Buddhism and Taoism were made state religions. Rulers institute isolationism policies and conservatism. Original Forbidden City and Temple of Heaven are built in Beijing.