Of torture Bernard [Gui] had very little to say. In only one of his 930 cases is it certain that he used it. He probably employed the method in vogue throughout Languedoc: starvation. A few days without food generally made a prisoner more willing to talk…Through all the centuries when the Catholic Church was creating a better civilization in Europe, torture had not been used in the secular courts. It had gone out of fashion during what are called the Dark Ages, and it had come back into fashion with the Renaissance, more specifically with the revival of Roman Law throughout the West during the twelfth century, at the very period when the Popes – particularly Innocent III, Honorius III and Gregory IX – were doing their best to put an end to the trial by ordeal. The courts of Frederic II used torture to extract confessions as a matter of course, when the judges had reason to believe the prisoner was concealing the truth…
Now, although Gregory IX had committed the Church to a cooperation with the state in the prosecution of heresy, and encouraged the secular magistrates to inflict the death penalty on the unrepentant, he apparently took it for granted, as most churchmen did for several years, that the Inquisitors were to act only as specialists in theology, and not in any sense as police officials. Canon law had previously condemned confessions extorted by pain, and it was generally felt that clergymen should have nothing to do with torture. As time went on and the secret enemy remained unvanquished, nay, boldly took the lives of Inquisitors here and there, those engaged in the perilous business felt more and more that they were locked in a desperate warfare with implacable and resourceful cohorts of the power of darkness; and as in all wars, they tended to become more ruthless as to the means. It was not until 1252, however, that Pope Innocent IV, in his bull Ad Extirpanda, opened the door for the introduction of torture in the Inquisitorial courts, by demanding that heretics be treated as ordinary criminals. To be sure, the Pope did not use the word “torture,” as several translations have made him appear to do so. What he actually said was, “Moreover, the podesta or ruler is required to compel all heretics whom he has arrested (short of injury to limb or danger of death) to confess their errors plainly, and to accuse other heretics whom they know, and their property, and followers and shelterers and defenders, as thieves and robbers of temporal goods are forced to accuse their accomplices and to tell what crimes they have committed; for these are truly robbers and homicides of souls, and thieves of the Sacraments of God, and of the Christian Faith”.
There is nothing here about the rack and the strappado, and strict confinement and deprivation of food were the only methods used in Languedoc more than half a century later. In other places the permission of Innocent was certainly understood as carte blanche for the Inquisitors to obtain information by the customary tortures, which, however, were applied by secular officials. This latter restriction made for delay and inefficiency, and presently the Inquisitors were complaining against the canon law which forbade clerics, under penalty of irregularity, even to be present in the torture chamber. In 1260 Alexander IV permitted them to grant one another dispensations from the irregularity so incurred. This permission, confirmed by Urban IV in 1262, was plainly a consent to evade the canon law, and therefore must be considered one of the abuses of the Inquisition. It was still understood, however, that torture was to be used only when the Inquisitor was convinced that the prisoner was concealing the truth, and when all other means of obtaining a confession had failed. The prisoner was then shown the instruments of torture and urged to confess. If he still refused, he was given a slight vexatio, which was gradually made more severe if necessary.
Obviously there were abuses of this dangerous privilege, and in 1311 Pope Clement V, who made many reforms in the Holy Office (insisting, for example, on cleared and more humane prisons instead of the dark holes in which prisoners were sometimes kept), decreed that no Inquisitor could ever use torture without first obtaining the permission of the bishop of the diocese. This was a tremendous limitation in favor of mercy.
William Thomas Walsh, Characters of the Inquisition (1940)