 He set himself to prove that the belief in witchcraft and magic was rejected by reason and by religion and that spiritualistic manifestations were wilful impostures or illusions due to mental disturbance in the observers.His aim was to prevent the persecution of poor, aged, and simple persons, who were popularly credited with being witches.The maintenance of the superstition he blamed largely on the Roman Catholic Church, and he attacked writers including Jean Bodin (1530–1596), author of "Démonomie des Sorciers" (Paris, 1580), and Jacobus Sprenger, supposed joint author of "Malleus Maleficarum" (Nuremberg, 1494).