Hucbald of St-Amand (HUGBALDUS, UBALDUS, UCHUBALDUS), a Benedictine monk; b. in 840; d. in 930 or 932. The place of birth of Hucbald is unknown. From the few data we have concerning his career we learn that he entered the Benedictine Order in the monastery of St-Amand-sur-l'Elmon, near Tournai, and that he added music to the other branches of study. Later he entered the Abbey of St-Germaind'Auxerre, where he completed his general and artistic education. In 883 we find him teaching in the Abbey of St-Bertin. In conjunction with Remi d'Auxerre, he reestablished, in 892, in the Diocese of Reims, the old church schools for singing. Hucbald made successful efforts to improve and supplement the neumatic notation in use in his time, which indicated the rhythm of the melody, but left the singer dependent on tradition for its intervals. After an attempt to make use once more of the Greek notation, he invented the so-called Dazia signs, which both designate the intervals of the melody and also serve to indicate definitely the character of the various church modes. But these signs, being clumsy and cumbersome, did not attain lasting favor as a system of notation. Hucbald later used lines and the first letters of the Latin alphabet as a means of fixing the intervals of the scale, and in this way became an important forerunner of Guido of Arezzo. Hucbald's principal achievement, however, consists in having given a theoretic basis to the custom of adding another melody to the chant of the Church, which custom he called organism, or diaphonia (see Counterpoint; Harmony), thereby laying the foundation for polyphony which developed from it. Hucbald's genuine works (Gerbert, "Scriptores", I) are "De harmonica institutione", "Musica enchiriadis", "Scholia enchiriadis", and "Commemoratio brevis de tonis et psalmis modulandis". On account of the discrepancy between some of the theories contained in the first-named treatise and those taught in the "Musica enchiriadis" and the "Scholia enchiriadis", which belong to a much later date in the long life of the author, Huebald's authorship of the last two works has been called in question, without good reason, however, since it has been pointed out that the "Scholia enchiriadis" is written as a sort of commentary or glossary on the author's first treatise and records the points wherein he had modified his theories.