 The Council of Vienne of 1311 proclaimed them heretics and the movement went into decline.The medieval Inquisition paid little attention to sorcery until Pope John XXII was the victim of an assassination attempt via poisoning and sorcery.In a letter written in 1320 to the Inquisitors of Carcassonne and Toulouse, Cardinal William of Santa Sabina states that Pope John declared witchcraft to be heresy, and thus it could be tried under the Inquisition.