Bernardo Gui (1261-1331) was a Dominican monk who from early inquisitorial got several positions in various parts of Western Europe and soon became known for his cunning and initiative in combating the heresies of the time, so as to have written a manual on inquisitorial methods that guided other famous character inquisidores.Para onlookers and friends of the "short" and "paste"
recommend short article from Wikipedia which, without being too long is pretty self explanatory. As a literary curiosity, I remember this historical character in the book by Umberto Eco "The Name of the Rose" as well as in the movie of the same name. In his Inquisitor's Manual "warns Bernard that you can not wear a Met
only infallible period to defeat the Evil One, and to do that is to give advantage to the forces Evil, which neutralize the strategies and tricks of the inquisitor. That said, the inquisitor must benefit both the answers of the defendants, as the testimony of the accusers, but also and especially of his own experience. Gui's work focuses mainly on five types unmask sects: the first of them would be the "Manichean" (founded in the area of \u200b\u200bpresent-day Iran in the late third century AD by the Persian sage Mani) which had a markedly dualistic belief in the spirit of man which belongs to God and the devil body establishing a constant struggle between them and the ultimate quest of victory the former over the latter. The second Gui-appointed heresy is that of "Waldenses" (founded in the late twelfth century AD in Lyon by a wealthy merchant named Peter Waldo) who practiced a primitive Christianity based on the sale of their property and starting a life of poverty and fellowship with the gospel. The third heretical group would be "pseudoapóstoles" or "Beghards" (a group formed around 1215 AD in Germany with a female version would be called "Beguine") who wore an austere life, living simply, communally reciting the office and praying regularly, being the pillars of piety, poverty and purity. The group would quarter that of the Jewish converts as Gui "return to the vomit of Judaism." The fifth and final set in the Manual of Bernard Gui are all the myriad of sorcerers, seers and summoners of demons "whose practices hurt much stinking purity of faith. "
I would add that each of these five groups go far, especially the first three, which met the common characteristics of poverty and early Christian life but differed in their dogma and rituals. Add that there were many more sects in those medieval centuries (and before and after) and they should be the future Protestant Reformation in all its variants.
To study these issues related to Christianity, the Church and the Middle Ages strongly recommend any book by two great English historians who specialize in these issues such as Theophanes Egido and Emilio Mitre Fernández.