Why did Calvinism grow so rapidly?

Calvinism was able to grow so rapidly for three reasons:

1.      Calvin’s theology was a complete, (almost) fully worked-out system which could fully take the place of Roman theology

2.      Calvinists embraced an active missionary style (or zeal, even) of the type presented by the early Church

3.      The founding of the Geneva Academy, from which many Calvinist leaders sprung

the great wall of china worked as a defense for the feudal states of the zhou dynasty to the north. during the warring states period more walls were put up to defend the borders of the different kingdoms. it was semi successful because despite the wall, the mongols eventually conquered china also the great wall provided protection to the economic development and cultural progress, safeguarded the trading routes such as the silk road, and secured transmission of information and transportation. @jayxboof