The Fallaciae in theologia is an anonymous, still unpublished text from the late twelfth or early thirteenth century on the errors that can be made in theological discourse. Ten manuscripts are known, dated from the thirteenth to fifteenth centuries. The author is probably a Parisian master, perhaps from the circle of Peter the Chanter. The fallacia equivocationis, as illustrated in the Fallaciae in theologia, is related to the fallacies committed by the heretic disciples of Amaury of Bène, according to Garnier of Rochefort in the Contra Amaurianos. In general, heretics are often accused of using fallacious reasoning during the Middle Ages.