Official URL: https://doi.org/10.1163/24055069-00401003

Within the mid-fourteenth century Parisian manuscript Paris, Bibliothèque nationale de France, latin 7378A, three as yet unedited music treatises are found, copied in a tiny, highly abbreviated script in a section of the manuscript devoted mostly to the music treatises of Jean des Murs. The incipits of the three treatises are as follows: ‘Omnes homines natura scire desiderant’, ‘Partes prolationis quot sunt’, and ‘Celebranda divina sunt officia in ecclesia’. Lawrence Gushee suggested that Jean des Murs may be their author, since Jean listed a book loan of a work authored by him with incipit ‘Omnes homines’ in the manuscript El Escorial, Real Biblioteca de San Lorenzo, O. ii .10, that contains his autograph annotations. This article focuses on the content of the second treatise, which appears to be closely related to Jean des Murs’s own Compendium artis musicae . The Compendium begins: ‘Partes prolationis quot sunt? Quinque’, whereas the answer to the same opening question posed in the BnF lat. 7378A treatise is ‘Quattuor’. The text of this treatise is considered as a witness to early ars nova theory as it relates to the theories propagated in Jean des Murs’s early works, and to the transmission of these texts within the layer of BnF lat. 7378A that is devoted to works by Jean des Murs and his contemporaries on music and astronomy.