Keywords: Collectio Avellana; Matilda of Canossa; Ius Commune.
This paper examines the revival of the "Collectio Avellana" in the eleventh- twelfth centuries, in order to find clues that may serve to shed light on the obscure origins of the collection in the VI century. The "Collectio" was copied in two manuscripts, commented on and annotated after having seemingly been forgotten for five hundred years. The analysis of these notes shows that the collection was widely used both in the Roman-Catholic and in the Imperial environments, in Italy and in Germany, for practical and administrative, or polemical, reasons. The results of this survey propose a new way of understanding the "Collectio Avellana": it was not an ordinary canonical collection but rather a special and "ante litteram" experiment of a "ius commune".