False Decretals (dĬkrē´təlz), collection of documents, partly spurious, treating of canon law. It was composed between 847 and 852 probably in France, either at Reims or in the province of Tours (specifically at Le Mans), and composed by a man who called himself Isidore Mercator (hence the term Pseudo-Isidorian Decretals); the date of composition is based on external evidence and localized chiefly on internal evidence. The collection was made to reform canon law and to support bishops in their perennial struggle against secular interference and interference from powerful metropolitans in diocesan operations. The collection established ancient legal sanction on episcopal demands for freedom from secular courts and from usurpation of diocesan properties on bare accusation. It gave sanction instead to the direct dependence of bishops on the Holy See without mediation of metropolitans and archbishops. The effect of the False Decretals was great in the Middle Ages. They were accepted to some extent by the papacy in support of its age-old claims. By incorporation and quotation in the Decretum of Gratian, the False Decretals received a definite authority in textbooks of canon law in the Middle Ages. The False Decretals have gained their chief fame because they were one of the great forgeries of history. Included in the collection are 60 letters or decrees of popes from Clement I to Melchiades (d. 314), of which 58 are forged; an original essay on the early church and the Council of Nicaea, with canons of 54 councils, of which all canons but one are authentic or were accepted as authentic long before the author's time; and a collection of papal letters from the 4th to 8th cent., of which the majority are authentic. Even in these sections, however, there has been tampering with the text. The forgeries are supported by liberal interlarding with quotations from authentic letters and by attribution to popes whose letters were known to be lost. Even many of the genuine letters in the collection show evidence of tampering. The False Decretals were completely exposed in the 16th cent.; among the many critics were Cardinal Nicholas of Cusa and Juan de Torquemada. The interpretation of the collection according to proper historical methods was not really begun until the 19th cent.