Final answer:
Guillaume de Machaut's compositions consisted mainly of polyphonic chansons.
Step-by-step explanation:
Guillaume de Machaut's compositions consisted mainly of polyphonic chansons. During the Medieval period, music was both sacred and secular. The liturgical genre, predominantly Gregorian chant, was monophonic, but polyphonic genres started to develop during the high Medieval era. The development of polyphonic forms is often associated with the Ars nova.