I am not 100% sure but I think it is: Cartels
<span>According to William H. McNeill, one way the plague affected China after 1331 was that it reduced the population drastically and led to economic depression. </span>
Mostly farming, lumbering, fishing, trading,etc. This required cheap labor, or slaves. They were required for the heavy work to be done quickly by demand.
They are both one of the largest religions in the world. :)
