In Medieval Europe, many people have been punished, many have been harmed, and many have been killed. And their prosecutor was someone known for loving and introducing the golden rule, their prosecutor was the Catholic Church. The Church has done a lot of good but many don’t realize they also have a vicious history of wrongfully murdering people with different religious beliefs; they would also slay enlightened people, whose knowledge contradicts the church, usually the ones the church kills where correct, only if they had the technology back then. This left Europe in a fear to strictly obey the church, or else. The Catholic Church has a darker sinister side that is unforgiving to those that oppose, and in medieval Europe, if you thought differently you would most likely regret it.
Heretics where one who opposed the teaching of the Catholic Church, the punishment for being a heretic was very harsh, it could even result in death. Like in the case of Galileo, he was correct with his theory of the solar system being heliocentric and not geocentric (the earth revolves around the sun, not the sun revolving around the earth), but since his theories contradict the church he was punished. (Starchild)It all started when Galileo started to study the tides, at first his theories are incorrect and posed no threat to the Catholic Church. But his conflict mainly starts in January of 1616 has new theories of the tides, that are in fact correct, and prove that the earth moves(.pbs.org), which opposed the church, since in the bible it states that "[the LORD] set the earth on its foundations; it can never be moved."(wiki/Galileo), Galileo is warned by Pope Paul V not to support Copernicus, Copernicus was before Galileo and was the founder of the theory of a heliocentric solar system, and claimed the earth spun on it’s axis. In 1624 Galileo had a hearing with Pope Urban VIII and other Cardinals, They allow him to discuss the Copernican theory, in his writings, but it can only be a hypothesis, nothing more. But Actually later on Pope Urban VIII allowed Galileo to write a book but it had to have views for and against heliocentric, and couldn't favor heliocentric. This book was known as Dialogue Concerning the Two Chief World Systems. But when it was published Galileo didn't obey the Pope and used his book to express his theories on a heliocentric solar system, this outrage the pope and Galileo was called to Rome. This time he was on trial for Heresy. And this time he was imprisoned, but because of his old age and condition, he was later sentenced to house arrest. Galileo was also forced to take back his heliocentric theories, and Dialogue Concerning the Two Chief World Systems, was banned. Also all of Galileo's future publications where banned, but this was not enforced. (wiki/Galileo) After all the Conflict in Galileo's life he got the last laugh, since he last words before he died where” But it does move!" (Referring to the earth). Galileo's life is an example and how the church put struggles on people's life in medieval time; because they believed the all powerful church was all ways right.
The Crusades were military campaigns called by the Pope to reclaim the holy land (Jerusalem) in the name of Christendom. The crusades are seen as very heroic. But usually after a city was captured. The Christians would massacre the Muslims in the city (this actually happened on both sides), and the crusades actually proved to be un-heroic. And after the first crusade back home in Europe mobs where actually forming and they would massacre the Jews in the town. Some Christians made attempts at protecting Jews in Church's, but the mobs would break in anyway and kill the Jews. (Weren’t they killing the Jews in the name of Christendom? so they still kill them when Priest and Bishops of the Catholic Church are protecting the Jews? ironic.). The Crusades where very popular in Europe, but back in the holy land the fighting was back and forth. When a Crusading Army would capture a city in the "Levant"(Area described for the holy land and part of modern day Iraq) it would usually soon be captured back by Muslims. Then the Pope would call another campaign, capture the city, exterminate the residents, and so on, and so on. (/wiki/Crusades) And exterminating the residents isn't an exaggeration it’s the truth, often every inhabitant was killed, despite age.
"It was a just and marvelous judgment of God, that this place [the temple of Solomon] should be filled with the blood of the unbelievers." St. Bernard announced before the Second Crusade that "The Christian glories in the death of a pagan, because thereby Christ himself is glorified." -Chronicler Raymond of Aguilers. (atheism.com) so the Crusade may be seen as a wonderful campaign to get the land back in the hands of the greedy Catholic Church, when actually many Innocent woman and children who weren't soldiers where slaughtered for no reason.
The Moors first invaded and settled in the Iberian Peninsula in 710 A.D. They (mainly Muslims) lived peacefully with Jews and Catholics for a few hundred years. The Spanish Inquisition was established in 1490 by King Ferdinand it was first installed to battle heresy, but soon turned to deal with the conversos(most said they converted, even thought they were practicing their old religion) Leading up to the Inquisition, in 1391 Ferrant Martinez began preaching anti-Jewish beliefs, Resulting in Seville hundreds of Jews where killed. Jews actually began converting to Christianity to avoid the fate of the Jews in Seville, This is when they become known as conversos, they do this so they can hide, but many conversos are caught for faking converting to be Catholics and are put on trial. Jews who stayed Jews also get in trouble for practicing Judaism with conversos. In 1492 the last Islamic foothold in Spain was Granada, but this was finally captured by Spain and all Jews and moors where expelled from Spain. About 160,000 Jews where deported. The Moors where finally driven out by 1492 (biblia.com). So now the problem was the Jew and the Conversos. Censorship was also used during the inquisition to help reform. Many books where banned. Jews weren't the only ones faking conversion moors also did it too, Moriscos. So many Moriscos where deported too, just like the conversos. Many conversos and moriscoc shared the same fate. At the end of the whole inquisition, about 50,000 trials where registered from 1560–1700. There where also cases of witches, but that wasn't much of a big deal compared to Germany, who burned about 100,000 witches at the stake. (wiki/Spanish_Inquisition) all this expelling and prosecuting was done because the different peoples did not agree with the teaching of the Catholic Church.
The Catholic Church had no room for opposition. If you believed the earth spun on its axis, and orbited the sun, you could have a horrible fate. Many scientist besides Galileo where tried for heresy, scientist even made secret cults where they can meet and discuss their finding without being prosecuted. Also it’s amazing that the Catholic Church is powerful enough to motivate armies to conquer distant lands, and rape and massacre the people that live there because they have different beliefs, they did all of this in the name of Christendom. The Church would even Support king to deport everyone who wasn't catholic or wasn't willing to convert out of the entire Iberian peninsula. The Church may have change, but at one time they could of would have been greatly feared by the many peasants and Europe and the Muslims in Spain or the holy land, and the Church was a forced to be reckoned with.