Europe during the Middle Ages was primarily Roman Catholic. By the Late Middle Ages, however, several factors were working against the church. First of all, there was the issue of the Muslims, who had not only defeated Europe in most of the Crusades, but had actually taken control of the Iberian Peninsula. Jews were moving to Europe, and creating an economic middle class. Pagan sentiments were rampant across the continent, and even those who remained Christian were often questioning the Mother Church and her decisions. In light of these events, it was decided in 1252 C.E. by Pope Innocent IV to begin a program of crushing heresy and ridding Europe of Jews, Muslims, and pagans by using fear, surprise, and an almost fanatical devotion to the Pope. Oh yes, and torture.... The Inquisition was infamous for torturing its victims, and always with an eye towards "saving their souls". Mock trials would be set up, in which the accused was almost invariably found guilty, after confession gained by torture.  This 400-year reign of terror even spread to the New World, where the indigenous population was subject to Inquisitional cruelty. Few people were willing to voice an opinion, or act differently from their neighbors out of fear of being turned in to the Inquisitors. Religious tolerance, scientific inquiry, and human rights came to a standstill. Not until the collapse of the Spanish Empire (the most important Inquisitional nation) and the Reformation did the institution itself finally fall apart.