There were no indications to guide an investigation until Díaz chanced to learn that, in the nunnery of Cangas (Oviedo), there were several nuns demoniacally possessed who were being exorcised by Fray Antonio Alvarez de Argüelles, a former fellow-student of his. It had for ages been the belief that possessing demons, under the torture of exorcisms and abuse lavished on them by the priest, could be compelled to reveal facts beyond human capacity to ascertain. Much of the current medieval conceptions concerning the spiritual universe were derived from this source and the practice of thus seeking knowledge for laudable purposes was recognized as lawful, provided it was done imperatively and not solicited as a favor. Even the gratification of idle curiosity with demons was merely a venial sin.[446] Froilan Díaz was therefore merely adopting a legitimate method when he suggested that the demons of Cangas should be made to reveal the causes of the king's illness, which would be a step to its cure. Rocaberti eagerly assented and applied to the Dominican Bishop of Oviedo, but that wary prelate hesitated to embark in a matter so dangerous and discouraged the suggestion. Díaz then addressed Argüelles, who at first refused but finally consented, if he could have written commands from the inquisitor-general and confessor. Rocaberti accordingly wrote, June 18th, to inscribe the names of the king and queen on a piece of paper, place it in his breast and ask the demon if either of them were suffering from sorcery; Díaz enclosed this in a letter of his own and arranged a cipher for the correspondence. The obliging demon swore by God that the king had been bewitched at the age of fourteen to render him impotent and incapable of governing. With this Argüelles endeavored to withdraw, but Rocaberti and Díaz were insistent that he should ascertain further particulars and antidotes for the sorcery and, on September 9th, he wrote that the spell was administered April 3, 1675 in a cup of chocolate by the queen-mother, in order to retain power; the charm was made with the members of a dead man and the remedies were inunction with blessed oil, purging and separation from the queen.