Cantus Firmus Mass

   A polyphonic setting of the Roman Catholic mass ordinary prayers using the same cantus firmus as the compositional basis for each one, thus creating a unified fivemovement mass cycle. (An English setting may omit the Kyrie, leaving it to be chanted because its text had been troped.) The cantus firmus may also refer to a particular feast or event for which the mass was composed; its source is usually given after the Latin word for mass, Missa, in the title of the work. The earliest examples, dating from the 1420s or early 1430s in England or northern France, are the {}Missa Alma Redemptoris Mater attributed to Leonel Power and the {}Missa Rex Seculorum attributed to John Dunstable. The technique dominated mass composition in the 15th century and gave way to paraphrase and parody techniques, without disappearing entirely, in the 16th. In England, it remained vital until the Reformation. The entire cantus firmus might be distributed over the three text sections of the Kyrie or repeated several times for the longer texts. In Guillaume Du Fay’s Missa Se La Face Ay Pale, one of the first to use a secular cantus firmus, both Gloria and Credo sound the melody three times in quickening durational proportions of 3:2:1, as in an isorhythmic motet. The melody might also be inverted, transposed, or sung in retrograde.