Mostly my high school history book, I expect. Here are about 100 woodcuts, mostly of historical multiple burnings and drownings of heretics, which I found in about 2 minutes in wikipedia.
http://www.bethelks.edu/services/mla/images/martyrsmirror/
Your logic is blurred by severe Christa phobia.
Your vision is blurred by a severe allergy to history books. Why don't you try reading one before you stuff your foot in your mouth clear to the knee?
Looking over my shoulder here, I've got somewhere between 300 and 400 historical books and books on history, a bit different than "history books" which are cursory works and summarize the editors opinions. These are a fraction of the material I'm familiar with. Additionally, I have a higher degree in European Medieval History. Your "high school" education is unfortunate, but not so much as you reliance upon it. So is your phobia concerning Christianity. People such as yourself take any connection to Christianity by people committing acts, as proof of the responsibility of Christianity for those acts. What is telling about this is that you make no similar connection to other religions, organizations, etc. Thus, you can make the absurd pronouncement that Hitler was a Christian. The woodcuts to which you refer, show how dangerous a little bit of knowledge can be. Propaganda is as old as History. One of the most common methodologies in the middle ages was for the local Prince to drum up support for his next campaign by depicting the enemy as heretical. Often this took the form of showing them persecuting faithful Christians. Later, Protestants greatly exaggerated the inquisition for the same reason. Finally, Europe wasn't converted in a day. Extreme barbarism like tossing their own children into pits to fight with dogs for the purpose of entertainment, wouldn't be expected to stop all of a sudden, and it didn't. A great deal of the heart of Europe wasn't converted until after the year 1000. Christianity brought a great deal of peace and civilization to Europe. The fact that evil did not cease is not surprising. Princes heavily indebted to Jews often began pogroms against them to get rid of their creditors. Was this done in the name of religion? Of course, what idiotic evil monarch would say, "Kill these people, so that I won't have to pay them back." Much better to say to the illiterate masses ignorant of Judaism, "These are wicked Christ killers." Of course, it takes a while for the effects of such evil to dissipate, so when too many new borns died or the like, a spontaneous persecution could occur. The Church during this time tried to hold a flock which contained hundreds of languages, differing peoples with histories of animosity and brutal customs, and a secular rule of warlords. Complicating this, was a precarious communication line that could take months and was almost always microcosmic in its scope. Not surprising then that even with the best of intentions, the Church would not be able to act decisively or that many of decisions now seem grossly unfair. By your standards of guilt, you must also find the US government directly responsible for instigating the actions of the KKK, but you have no such standards, just a deep dislike of Christianity.