The manuscript Seville, Biblioteca Colombina y Capitular 5-2-25, a composite of dozens of theoretical treatises, is one of the primary witnesses to late medieval music theory. Its numerous copies of significant texts have been the focus of substantial scholarly attention to date, but the shorter, unattributed, or fragmentary works have not yet received the same scrutiny. In this monograph, Cook demonstrates that a small group of such works, linked to the otherwise unknown Magister Johannes Pipudi, is in fact much more noteworthy than previous scholarship has observed. The not one but two copies of De arte cantus are in fact one of the earliest known sources for the Libellus cantus mensurabilis, purportedly by Jean des Murs and the most widely copied music theory treatise of its day, while Regulae contrapunctus, Nota quod novem sunt species contrapunctus, and a concluding set of notes in Catalan are early witnesses to the popular Ars contrapuncti trea
