THOMAS, PIERRE. - Benedictine monk of the abbey of Clervaux, b. at Mouroux (France) on 15 July 1906, d. at Rome on 19 Dec. 1951.
Having graduated in Rome from the Pontifical Institute of Sacred Music, he was immediately appointed there to teach Gregorian theory, history, and palaeography. He wrote numerous articles in Bollettino Ceciliano, Ephemerides liturgicae, « Ambrosius », « La vie bénédictine » of Ligugè, and « Cecilia » of Boston; he directed and left various transcriptions of Gregorian and post-Gregorian pieces; he was also an active contributor to the Enciclopedia Cattolica for articles on Gregorian chant.
For years he had been preparing a critical edition of unpublished medieval musical treatises, and he published on several occasions studies on modality and rhythm, on practical interpretation, and on the palaeographical exegesis of Gregorian chant. He endowed the Pontifical Institute of Sacred Music with a significant collection of microfilms reproducing hundreds of Gregorian and polyphonic codices, obtained from the various libraries of Europe. A special place belongs to the monographic study Le chant et les chantres dans les monastères bénédictins antérieurs au XVe siècle, published in the Mélanges 1947, edited by the abbey of S. Girolamo.