The 76 medieval documents that are transcribed in this book constitute all the medieval documentation preserved in the local institutions in the current "Cuadrilla" of Campezo. Of the six municipalities that are in it, only Peñacerrada lacks any documentation prior to 1520. The texts have been searched for in the six municipal archives as well as in the various Administrative Boards that still preserve very ancient documents, in general about the establishment of rights on communal terrains. Within a zone marked by the fact of being the border with the Kingdom of Navarre, the documents are centered in three matters: In the first place, the establishment of towns in this area, reflected in the leaves of population (fueros de población) for Santa Cruz de Campezo and Corres and in the privileges that prove the foundation of San Vicente de Arana, to which one must add the jurisdictions of Antoñana and Bernedo that are not transcribed because are they have not been preserved in their municipal archives. Secondly, the distribution of terrains, with numerous delimitations and agreements signed by the villages in order to establish rights over communal terrains. And finally, the 15th century and early 16th century letters of implementation that reflect the confrontation maintained by these communities with their lords in order to put a limit to their attributions.