Copies of 9 documents relating to the illicit use of water and diversion of waterways in the territory of Milan, presumably to compile evidence of the legal status of these assets. The first 8, copies of documents originally written in 1382 to 1386, are from the correspondence of Blanche of Savoy, widow of Galeazzo II Visconti, and their son Giangaleazzo Visconti, Duke of Milan, first requesting that the Vicarius of Milan forbid the diversion of water and sue those having diverted water from the Rugia Sancti Columbani (San Colombano) and its tributary the Modio, and then recounting the proceedings of the ensuing lawsuits. The seventh and eighth documents have copies of notarial signets (f. 37v, 39r). The last document (f. 39v-43r) is a decree of Duke Filippo Maria Visconti dated 18 April 1444 prohibiting diversion of rivers and canals without permission. It begins with a note explaining that it was found at the Officium statutorum (f. 39v). The copies appear all to have been written at roughly the same time. Contemporary annotations, as well as annotations in 16th- and 17th-century hands, appear in the margins.