其实，历史上的宗教斗争，主要是自相残杀。根据历史学家的研究，从尼禄到康士坦丁，死于所谓迫害的基督徒加起来不超过两千。而基督徒杀死不同教派（如路德教），一次就是十万。十字军东征时，西欧各信教蛮族大量杀戮拜占庭帝国的教徒（其教义区别是三位一体还是一个上帝），是罗马帝国最终灭亡的主要原因。
The History Of The Decline And Fall Of The Roman Empire
http://www.ccel.org/g/gibbon/decline/volume1/chap16.htm
“it must still be acknowledged that the Christians, in the course of their intestine dissensions, have inflicted far greater severities on each other than they had experienced from the zeal of infidels.... In the Netherlands alone more than one hundred thousand of the subjects of Charles V. are said to have suffered by the hand of the executioner"
http://www.ccel.org/g/gibbon/decline/volume2/chap58.htm#First
the paths of pilgrimage were obliterated; the chiefs themselves had an imperfect notion of the length of the way and the state of their enemies; and such was the stupidity of the people, that, at the sight of the first city or castle beyond the limits of their knowledge, they were ready to ask whether that was not the Jerusalem...Their rear was again pressed by a herd of two hundred thousand, the most stupid and savage refuse of the people, who mingled with their devotion a brutal license of rapine, prostitution, and drunkenness....
