The Chinese resorted to isolating themselves because lightening had struck and burned the royal palace to the ground. The emperor took this to be a
sign of punishment or anger from the gods because they were exploring outside of China; thus, he ordered Zheng He, who was currently at the tip of
Africa, to return to China.
It has been a while, but I was somewhat interested in china and its history once, took a couple of classes during undergrad. I believe that China as
we know it today did not REALLY form until the adoption of communionism with Mao in the 50's! Before then the area we now call china was a varing
grouping of feudal states...
It is getting late and my spelling is worse then normal, sorry...