This raises the interesting question of what is religious violence. This is not as easy as it sounds. Pinker notes (with an apparent rhetorical smirk):
World War I, as I recall, was a war fought mostly by Christians against Christians.That "as I recall" bit is pretty cute, and he seems to have written it as if it were meant seriously. But if that is his criterion then gandersauce requires us to count all the black men who were lynched by Democrats in the 1910s-1940s. World War I was also fought mostly by modern scientific Europeans against modern scientific Europeans. So what? It remains to be shown that Imperial Germany, Austro-Hungary, France, England, et al. went to war because they were Christian or modern scientific Europeans, or that mobs of Democrats lynched black men because the lynch mob were Democrats.
Pinker seems impressed with what people call themselves or he would not have made that fatuous remark about WW1. North Korea calls itself a democratic republic, but need we take the claim seriously? If the Europeans of 1914 were Christians, they were simply members of the State Established Churches. Worship of the Nation had by then long submerged worship of God. War posters like the one on the left cited the State or the Folk, but not the Church.
Or as our old buddy Tommy Aquinas put it, there is a difference between a human act and the act of a human. The former is what a man does because he is a human; the latter is merely something that he does. In the same way, a scientist (e.g., Fritz Haber) might devise a new means of mass murder (poison gas) for the Great War; but does he do it because he is a scientist or because he is a patriotic German? I don't mean his technical skills, but his motives.
Even when there seems to be a "because-ness," closer inspection reveals greater complexity. Sure, there was a time when you could gin up a crowd to lynch someone because he was a dirty stinking Calvinist and this here is Lutheran land. But there are times and places when you could do the same thing using race or ethnicity or even economic commitments. If human beings are prone to violence, then it may not matter much what is used to incite them.To read the whole post (on a more general topic) that this is extracted from, click here
Thus when we examine the Huguenot wars in France, what we discover is that three Great Houses were fighting for control of the French throne, and they swung back and forth between Calvinism and Catholicism as the needs of state dictated. "Paris is worth a Mass," Hank Bourbon famously declared as he shed his Calvinism for convenience. A more accurate title would be the War of the French Succession.
Even the Thirty Years War is iffy. The German princes did not declare themselves independent of the Empire because they had become Protestant; they became Protestant because they wanted to declare their independence of the Empire. And can a war in which the Pope and the French crown supported the "Protestant" side really be called a religious war? It was really a war between Bourbon and Hapsburg, with both Protestant and Catholic princes on both sides.
Heresy was often a surrogate for political disloyalty, which is why heretics were more severely persecuted by the secular power. The church authorities were derided as "soft-hearted" (clericalem verens mollitiem) because they preferred persuasion.
Take another look at Pinker's list of the top nine [destructive atrocities of all time], above. Note that the top six are all pre-Christian and non-Christian events. And the last three date from after the subordination of the Church to the secular State; that is, after the Concordances, the English nationalization, and cuius regio, eius religio.