Perhaps not totally on topic... But it's background. It's one of my favorite periods of history to study. In a way we're still paying for it.
The Thirty Years War
The Thirty Years War was also, at least in part, a religious war among Catholics, Lutherans and Calvinists. Ferdinand II and, to a lesser degree, his primary ally Maximillian I represented the re-Catholicizing zeal of the Jesuit Counter-reformation, while Frederick V of the Palatinate represented the equally militant forces of Calvinism.
Don't forget the Crusades. You can't get any more violent than that.
The genocide of native peoples was in great part driven by religious bigotry.
You can read up on the United States' very own Religious War... This was the English Civil War as fought in the Colonies...The Plague of the 1620's, The "War Effort" (1620's), and Crypto-Catholics
. You can also find information on this in Kevin Phillips' "The Cousin's Wars"