Available in English for the first time, Prosdocimo's Tractatus plane musice (1412) and Tractatus musice speculative (1425) are exemplary texts for understanding the high sophistication of music theory in the early fifteenth century. Known for considering music as a science based on demonstrable mathematical principles, Prosdocimo praises Marchetto for his theory of plainchant but criticizes his influential Lucidarium for its heterodox mathematics. In dismissing Marchetto as a "mere performer," Prosdocimo takes up matters as broad as the nature and definition of music and as precise as counterpoint, tuning, and ecclesiastical modes. The treatises also reveal much about Prosdocimo's understanding of plainchant; his work with Euclid's Elementa; and his familiarity with the music theory of Boethius, Macrobius, and Johannes de Muris. A foremost authority on Italian music theory of the Middle Ages and early Renaissance, Jan Herlinger consults manuscripts from Bologna, Cremona, and Lucca in preparing these valuable first critical editions.

"Prosdocimo's writings deserve to be better known, not only to music theorists, but to scholars in all of the fields in which he was active. This edition is a valuable contribution to that objective."—Renaissance Quarterly

"It is a blessing to find a rich Index verborum in which to look for references to individual terms."—Plainsong and Medieval Music

Prosdocimo de' Beldomandi was a professor at the University of Padua until his death in 1428 and the author of eight musical treatises. Jan Herlinger is the Derryl and Helen Haymon Professor of Music at Louisiana State University, and the editor and translator of Marchetto of Padua's Lucidarium in arte musice plane and two other treatises by Prosdocimo.