Abstract

The two most ancient and important manuscripts in the "Collectio Avellana" were produced and circulated within some monastic institutions linked to Matilde di Canossa and hence to the Gregorian movement: the Nonantola and Polirone monasteries and the Fonte Avellana hermitage. Some quotations from the letters of "Collectio Avellana" in the "Collectio canonum" of Anselmo da Lucca, one of the most authoritative exponents of the Gregorian party, confirm their reception in the Gregorian context. Nevertheless, this does not authorise us to claim that the "Collectio Avellana" was used solely within Matilde of Canossa's circle. In point of fact, two letters from the "Collectio Avellana" are used and skilfully manipulated in the Defensio Henrici IV, which was written by Crasso, one of the supporters in Ravenna of antipope Clement III. This confirms that during the investiture controversy the same canons were used, and frequently manipulated, in order to support opposing arguments.