<P> European polyphony rose prior to, and during the period of the Western Schism . Avignon, the seat of the antipopes, was a vigorous center of secular music - making, much of which influenced sacred polyphony . </P> <P> It was not merely polyphony that offended the medieval ears, but the notion of secular music merging with the sacred and making its way into the papal court . It gave church music more of a jocular performance quality removing the solemn worship they were accustomed to . The use of and attitude toward polyphony varied widely in the Avignon court from the beginning to the end of its religious importance in the fourteenth century . Harmony was not only considered frivolous, impious, and lascivious, but an obstruction to the audibility of the words . Instruments, as well as certain modes, were actually forbidden in the church because of their association with secular music and pagan rites . Dissonant clashes of notes give a creepy feeling that was labeled as evil, fueling their argument against polyphony as being the devil's music . After banishing polyphony from the Liturgy in 1322, Pope John XXII spoke in his 1324 bull Docta Sanctorum Patrum warning against the unbecoming elements of this musical innovation . Pope Clement VI, however, indulged in it . </P> <P> The oldest extant polyphonic setting of the mass attributable to one composer is Guillaume de Machaut's Messe de Nostre Dame, dated to 1364, during the pontificate of Pope Urban V . </P> <P> More recently, the Second Vatican Council (1962--1965) stated: "Gregorian chant, other things being equal, should be given pride of place in liturgical services . But other kinds of sacred music, especially polyphony, are by no means excluded...Religious singing by the people is to be skillfully fostered, so that in devotions and sacred exercises, as also during liturgical services, the voices of the faithful may ring out". </P>

Which person or group brought polyphonic music into the christian church