Between the years 1390 and 1435, Dunstable Power produced polyphonic motets that are still worthy of attention. Dunstables "Quam Pulchra Es" is a three-part motet. It concludes with an Alleluia being far in advance of any similar work during the first quarter of the fifteenth century. It exemplified a genuinely artistic style.
Equally beautiful are the motets of Lionel Power, the manuscripts of which are at Vienna, Bologna, and Modena. One of his happiest efforts is a four-part motet in which the treatment is peculiarly melodious and of an Irish flavor.
During the late 13th century, motets with tenors sharing similar rhythms with the upper voices became possible. Several motet types blossomed in France, but reduction in diversity occurred because of the acclaimed works of Philippe de Vitry, who died Bishop of Meaux. He wrote a work entitled "Ars Compositionis de Motetis", the date of which was probably 1320. This volume (now in the Paris Bibliothèque Nationale) contains our oldest specimens of sacred motets, and these continued to set trends for over two centuries.
Machaut's motets also showcased a preference for French texts. Guillaume de Machaut used isorhythm in the tenor and occasionally the upper parts as well. His signature became increasingly common in the late 14th century along with rhythmic refinements. Many complex motets of this sort can now be found in English and French sources of the late 14th century and early 15th century. Although he wrote music for more than one hundred of his French poems, and even for half a dozen motets in Latin, Machaut remains best-known for his Mass of Notre Dame. This mass was written as part of the commemoration of the Virgin endowed by the Machaut brothers at Rheims, and was intended for performance in a smaller setting by specialized soloists. The most striking aspect of the piece is not simply the high quality of the contrapuntal writing, but the architectural unity of the Ordinary sections as well. Machaut's mass was not the earliest surviving mass cycle, however it was the earliest by a single composer and indeed the earliest to display this degree of creativity.
Guillaume Dufay, in his 14 isorhythmic motets, achieved a magnificent synthesis of numerically constructed cantus firmus polyphony with the new techniques that hastened its decline. A cantus firmus is a melody to which one or more contrapuntal parts are added. It is traditionally written in alto clef and often begins and ends on the tonic of the key or the final of the mode. The penultimate note may be the note a step above the tonic or final.
Dufay, who was a Walloon, composed numerous motets, including "Salve Virgo", "Flos forum", "Alma Redemptoris", and "Ave Regina caelorum". He spent the majority of his career in Cambria. He joined a choir with fifteen to twenty other members, originally. As the years passed, members, including Dufay, moved to other choirs for money and other such reasons. Guillaume Dufay was a chief figure of music schools because of his completion of education as a choir master, as well as being very well-educated in most aspects of music. Guillaume Dufay was the first composer to use a folk song in mass. Thus, he requested that the last named exquisite composition be sung by the altar boys...