it is not religion that caused it it is the very basic function of a human that caused the wars, by that i mean the function that we have to believe in order to see, and no i am not getting that backwards i am saying it in that way because it is true. so they believed in there religion and they did whatever to still see what they believe and not to be proven wrong.
do this read, go ahead i know you want to.
just kidding, but do read this it tells you more about this. http://www.popularmechanics.co.za/article/a-trick-of-the-mind-2011-11-24