Under the Mongol rule, there was a time of peace. This was called Pax Mongolica. One reason why this was a time of peace was because it made silk trade safer. My teacher once told the class that a merchant can balance gold on top of their heads and reach their destination without any raiders/robbers coming after it.
Not only did it result in safer trading, but the borders of China was secured unlike the previous dynasties which had trouble protecting its borders from outside forces.
Hope this helps!!!