Why did buddhism spread widely in china by the 6th century?

Buddhism widely spread in China by the 6th century for Buddha had followers who spread his teaching throughout China after he died. The widespread acceptance was because Buddhism and Taoism has similarities through its concepts of “emptiness” even though the term meant different things in each tradition.

Moreover, the imperial families had adopted Buddhism as their own spiritual tradition and even produced its own Buddhist masters.

the answer is not negative reinforcement.