In this form the entire initiative was taken by the Inquisitor, who was both prosecutor and judge. His first task was to examine the accused and the witnesses. For this purpose Eymeric developed a technique as elaborate and painstaking as anything in the history of jurisprudence. He provided a form for every conceivable emergency. He even suggested the questions that the Inquisitor should ask each witness concerning the accused…
If the witness replied that the remarks were made in jest or in anger, the Inquisitor must not be too gullible, but must investigate further to make sure, “for almost all modern heretics excuse themselves in this way”. Let him find the truth, so far as possible, and then proceed. If the accused really was angry or joking, he was not to be prosecuted for heresy…
It was the general policy of the Inquisition not to convict a man for a slip of the tongue, but to warn him gravely to avoid it in the future. Likewise heretical statements were not to be taken seriously if they came from a person who was drunk, talking in his sleep, senile with age, or too young to know the significance of his remarks.
To avoid any possibility or suspicion of fraud, all witnesses had to be examined in the presence of a notary, preferably some public official of importance, two religious or at least reputable persons, and the Judge.
The next step was the examination of the accused. He was put under oath and asked many set questions about himself, his parents, and so on. He was not to be arrested until he confessed, or until the Inquisitor had strong reasons, from the testimony of at least two witnesses…for believing him probably guilty. To commit him to prison, however, the Inquisitor must first obtain the consent of the Bishop.
It was the understanding of all the great jurisconsults of the Inquisition that the Inquisitor, in all his examinations, should deal with people “humanely, remembering that he himself is a man, who could commit similar offenses, if he were not borne up by the grace of the omnipotent God, and that he should deal with the culprit according to his quality and dignity” (Directorium Inquisitorum).
William Thomas Walsh, Characters of the Inquisition (1940)