A while ago I mentioned for someone to read up on the wars between the Caths and Prods during The Reformation and while I knew the 30 Year War was part of it, I myself didnt realize the depth of it.
The Catholic Church was obviously corrupt throughout the middle ages - and this corruption resulted in regular calls for reform and improvement. Pope John XII had open love affairs. Urban VI tortured and murdered some of his cardinals. Innocent VIII proudly acknowledged his illegitimate children and heaped church riches upon them. Simony and nepotism were rampant. Most efforts ended in the reformers being called heretics and dying for their trouble.
In the 1100s, Arnold of Brescia was excommunicated, hanged and then burned. John Wycliffe of England translated the bible into English, and his followers were later hunted down and killed. John Hus from Prague was excommunicated then in 1415 he was captured and burned, despite the fact that he had a letter of safe passage from the Emperor.
But eventually the weight of the reformers grew strong enough to survive, but only at the cost of millions of lives as the Protestant Reformation battled the Catholic Counter Reformation in towns and fields throughout Europe. Martin Luther's 95 theses, nailed to a church door, set off a fire storm of violence and blood. German princes managed to fight Catholic armies to standstill by 1555, which resulted in the Peace of Augsburg. Protestant "heretics" were allowed to live in Germany, but that level of tolerance was not extended to other countries.
Unfortunately, that "peace" didn't last - from 1618 to 1648 Europe experienced The Thirty Years' War which left Germany a wasteland after millions and millions were slaughtered. Catholic armies under the leadership of Catholic Emperor Ferdinand II kept defeating Protestant armies, but then made the mistake of trying to eliminate Protestantism completely, engaging in terrible repression and persecution.
This caused new Protestant armies in foreign lands like Denmark and Sweden to be called up to oppose him. The result of all this was a victory for no one, and an estimated drop of Germany's population from 18 million to 4 million. With too few people left to work the field and trade for goods, starvation and disease ravaged the miserable survivors. Such are the fruits of European Christianity.
Catholics Killing Protestants
In France, the largest Protestant group was known as the Huguenots. They were mercilessly persecuted, and King Henry created a heresy court known infamously as The Burning Chamber because that was the standard punishment for heretics. On the night of August 24, 1572 - known as St. Bartholomew's Day - Catholic soldiers swept through Huguenot neighborhoods of Paris in a foreshadowing of what would happen to the Jews under Nazi rule.
Thousands were slaughtered in their homes and other massacres timed for the same night occurred in cities across France. In response to this, Pope Gregory XIII wrote to France's King Charles IX: "We rejoice with you that with the help of God you have relieved the world of these wretched heretics."
Pope Pius sent Catholic troops into France to aid in the repression efforts, ordering the army commander to kill all prisoners. Pius, unsurprisingly, was later canonized as a saint. In the Catholic Church, sainthood is an honor which goes not to the nicest person or to someone who has aided humanity, but to those Catholics who have done great deeds to advance the cause of Catholicism. As a result of such treatment, Huguenots fled France in large numbers. One group reached what would later become Florida - and when they were discovered by a Spanish expedition, all were killed.
In Flanders, all heretical Protestants were ordered executed and thousands were burned at the stake. But queen Mary was merciful to Protestants who recanted - instead of burning, the men would be killed by a sword and women buried alive. Philip II, Spanish king and also ruler of Holland and Belgium, was positively obsessed with eliminating Protestantism and ordered that all prisoners be killed so that there would be no chance that they might escape through neglect or mistakes. The Duke of Alva was sent in and began what became known as the "Spanish Fury" in which thousands of Antwerp Protestants were killed and almost all "heretics" in Haarlem were massacred.
Protestants Killing Catholics
Of course, Protestants should not be imagined as innocents in all of this. Attempting to abandon several centuries of developed church tradition, Protestant theology focused instead upon stricter adherence to scriptures. As an example, the harsher laws of the Old Testament developed greater prominence in Protestant lands than they did in Catholic lands. Protestant leaders also embraced some of the nastier doctrines of a few Catholic theologians, like Augustine's ideas about free will and predestination. Luther wrote in 1518: "Free will after the Fall is nothing but a word. Even doing what in him lies, man sins mortally."
In Switzerland, John Calvin created a vicious theocracy in which morality police were employed to control people's behavior. Citizens were harshly punished for a wide variety of moral infractions, including dancing, drinking, and generally being entertained. Theological dissidents were summarily executed, like Michael Servetus who was burned for doubting the Trinity. It isn't surprising that some of the nastiest Christians in America today, like Christian Reconstructionists, are unabashed Calvinists
During the many Huguenot wars ravaging France, Huguenot soldiers hunted priests like animals and one captain is reported to have worn a necklace of priests' ears. In England, after King Henry VIII created the Anglican Church, he went after both Catholics and Protestants. Catholic loyalists like Sir Thomas More were quickly executed, but Lutherans who doubted retained doctrines like transubstantiation were also not spared. When his daughter Mary reached the throne in 1553 she became known as "Bloody Mary" because she attempted to reinstitute Catholicism through violence - but she only managed to make the country even more Protestant.
Unsurprisingly, not all Protestants were created equal - some wretched groups were uniformly hated by all parties. One example of this is the Anabaptists, who were martyred for their faith in huge numbers. Anabaptists briefly took the German city of Munster, but Catholic armies regained control, torturing to death Anabaptist leaders with red-hot pincers. Their bodies were hung in cages from a church steeple where they remained for many years as a visible reminder of what happens to those who dare to oppose church authority.
Once again, there is quite a lot more to cover on the topic of religious violence, but I think that we've seen even more now which should lead reasonable people to conclude that religion in general, and Christianity in particular, doesn't do a very good job at all in preventing human violence. At a minimum, it does a wonderful job at serving as a justification for violence. In many cases, however, religious beliefs and attitudes appear to form the basis for violent acts or movements. In these instances, the violence would not have occurred if it had not been for religion.