Organ Mass

   A principal practice of alternatim by which organ versets substitute for chanted portions of the ordinary and proper prayers of the mass in alternation. The earliest versets are found in the Faenza Codex (Italy, c. 1400). In 1600, Pope Clement VII’s {}Caeremoniale Episcorporum ("Bishops ceremonial") ratified this long-standing practice. At that time, the organ typically played 19 versets: five for the Kyrie, nine for the Gloria, two for the Sanctus, one for the Benedictus (entire text), and two for the Agnus Dei. The document also called for soft organ music during the Elevation (Consecration) and at the end of mass. The Credo could not be performed {}alternatim after the Council of Trent. The division of proper chants varied widely; the Offertory enjoyed particular freedom of treatment. In general, the relation of the versets with original chants grew ever more distant until the Tra Le Sollecitudini of Pope Pius X (1903) banned alternatim practice altogether. However, the tradition of organ improvisation during chanted masses continued in France, and Olivier Messiaen composed Messe de la Pentecôte in 1951. Publications of organ masses peaked in the 17th century. Particularly important are Girolamo Frescobaldi’s Fiori Musicali (1635), Antonio Croci’s Frutti musicali (1642), Guillaume Gabriel Nivers’ {}2e Livre d’Orgue (1667), Nicolas-Antoine Lebègue’s Second Livre {}D’Orgue (1678?), André Raison’s Livre D’Orgue Contenant Cinque {}Messes (1688), Nicolas de Grigny’s Premier Livre d’Orgue (1699), and above all François Couperin’s Pièces d’Orgue Consistantes en {}Deux Messes (1690).