For these and other reasons, the devil assumed greater prominence during the fourteenth and fifteenth centuries than ever before. Men believed that he might appear to them from behind every hedge or ruin, that his action was to be seen in almost all pains and diseases, but that he was to be dreaded most of all when he entered into a league with some man or woman. Thus everything was ready for the outbreak of witch mania when, in 1484, Pope Innocent VIII by his bull _Summis desiderantes_ gave the sanction of the Church to the popular beliefs concerning witches, such as sexual intercourse with devils, destruction of crops, and infliction of sterility and disease on man and beast. The charge of sorcery had usually been employed in earlier times either to check learned men who seemed to be going too far, or tending to heresy in their researches, as in the case of the physicians Arnold of Villanova (1240-1312) and Peter of Abano (1250-1320), or to crush individuals and societies who were politically dangerous, as with Joan of Arc, the Duchess of Gloucester, and the Templars--the Church being called in to aid the civil power. Now it was the Church which called upon the civil power to assist in a crusade against witches and sorcerers as being the worst and most dangerous of heretics. In the Middle Ages it was held that a man who called up the devil, knowing it to be wrong, was not a heretic but merely a sinner. But if he thought it was not wrong, or that the devil would tell him the truth, or that the devil could do anything without God’s permission, he was also a heretic, since these beliefs are contrary to Church doctrine. In the fifteenth century it was taught that all sorcerers are heretics, _maleficus_ being, according to the learned authors of the _Malleus Maleficarum_, a contraction of _male de fide sentiens_ or heretic.[276] Nor was the identification of heresy and witchcraft illogical, whatever we may think of the etymology. The Church is the kingdom of God, heretics form the kingdom of the devil, and just as the Church possesses saints who see visions, work miracles, and commune with Christ face to face, so there are specially eminent heretics, saints of the devil’s church, who work miracles and have obscene intercourse with their master. All true Christians are potential saints, all heretics potential sorcerers, for all have committed treason against the divine Majesty, though only some may have entered into a definite compact with the enemy. The former, if they repent, may hope for perpetual imprisonment; the latter are to be put to death whether they repent or not.