Now, when did sorcery clearly involve heresy? It was not difficult to argue that it invariably did. Sorcery was invoking demons, trafficking with Satan, and to do this a man must surely entertain heretical ideas about Satan and demons. Certainly, if a man dealt in such trafficking, holding it to be not sinful, he was a manifest heretic.[195] Again, to seek to acquire knowledge of the future from Satan, the future depending solely on the Almighty, involved heresy. Under the title, sorcery, there came to be included astronomy's parent, astrology.[196] Some men of unquestioned orthodoxy gave their sanction and support to it, notably Cardinal D'Ailly; and it was not apparently definitely forbidden during the thirteenth and fourteenth centuries in ecclesiastical formularies. But clearly, although there was no question of invoking demons in connection with astrology, on the other hand, the astrologer by maintaining that a man's destiny was controlled by the conjunction of stars and planets at his birth was denying the freedom of the will, questioning the omnipotence of God, consequently being guilty of manifest blasphemy and heresy. Accordingly, the astrologer was always liable to prosecution by the Inquisition. The best security lay in the fact that belief in astrology was extremely widespread among all classes of society, among clergy as well as laity, of whatever degree of education. In the fourteenth century there was a marked increase in sorcery. This was probably the direct consequence of persecution on the grounds of heresy--such persecution being in a way the highest possible testimony to its genuineness. For the Inquisition never dealt with a reputed magician as a charlatan; it dealt with him as one really in league with Satan. Otherwise there would have been no heresy involved. The attitude of the Church towards sorcery--its attribution of heresy to the magician--actually put a premium upon sorcery. The sorcerer was the more in request because people were more than ever convinced that his claims were well founded, and he was able to make more out of his calling because it had become precarious. For these reasons the extreme zeal of Pope John XXII against all workers of magic failed in its object. In 1317 he satisfied himself, on grounds good or bad, that several persons in his household had been plotting to take his life. Under torture they stated that they had first had recourse to poison, but that that ordinary humdrum method having failed, they had next invoked the assistance of demons to accomplish their purpose. The Pope was roused to thorough and energetic action, and started a resolute campaign against the accursed race of magicians. Dissatisfied with the ambiguous terms of Alexander IV's directions to the Inquisition in matters of sorcery, he gave it direct authority in such cases and urged it to earnest efforts.[197] Ten years later, however, for some reason or other, he withdrew this jurisdiction from the Inquisition; and it is to be gathered that there ensued a period of comparative immunity for sorcery until 1374, when Gregory XI once more entrusted the task of prosecuting magicians to the Holy Office.