dufay wrote church music including masses, motets, magnificats, hymns, simple chant settings and antiphons. his secular (non-religious) music includes rondeaux, ballades, virelais and a few other kinds of chanson. his style of composition laid the foundation for the next generations of renaissance composers. some of his techniques were old-fashioned. he used isorhythms in his motets, which had been popular in medieval music. he used a way of harmonizing chants which became known as fauxbourdon. he was popular because he was skilled at writing melodies which were beautiful to sing.