Why was ancient China isolated?
We need to go beyond the Mongols to answer this. The Tang and Sung dynasty before the Mongols already had some contacts with the outside world but these were minimal. The ancient Chinese had a worldview which perceived themselves as the centre of the world, hence the term ‘zhong yuan’. They were self sufficient and technologically advanced. They regarded foreigners as being inferior to themselves and were not active in establishing links with the outside world.