We do not know definitely when the Inquisition was first employed against witchcraft; but certainly in 1374 it was determined by the papacy that the Holy Office was competent to try such cases.[220] In 1437 Eugenius IV called upon inquisitors everywhere to exert themselves against the evil.[221] And there is no question that throughout the fifteenth century the tribunal carried on a crusade against witchcraft with great assiduity. Although Sprenger was moved to confess that the extirpation of the pest seemed an impossibility, being inclined to lay the blame on the carelessness and inactivity of the secular authority,[222] nevertheless the number of executions was terrible. We are told that in a single year the Bishop of Bamberg destroyed six hundred witches, the Bishop of Würzburg nine hundred.[223] A thousand perished in the same space of time in the diocese of Como.[224] The execution of witches, then, both in this century and the next, assumed great proportions, largely owing to the thoroughness of inquisitorial proceedings, though it must be added—despite Sprenger’s animadversions upon its slackness—that actually the civil authority was responsible for many. The Inquisition, therefore, must bear much of the blame for the spread of witchcraft, or rather—for it amounted to the same thing—for the witchcraft craze. Largely in its records were collected the great stores of indisputable evidence of the reality of that heresy which it had become one of the functions of the tribunal to eradicate. By reason of its constitution and its methods of procedure the Inquisition was always a very effective court; but it was especially so in the case of witches, because in dealing with them the inquisitor felt that he was engaged in a personal combat with Satan himself, and that he had to exert all his powers in order to withstand, still more to overcome, so formidable an adversary. Indeed it was very fortunate that he was able to comfort himself with the knowledge that he was impervious to the attacks of witchcraft. Nevertheless it was felt necessary to take special precautions.[225]