Guillaume Dufay was born in Cambrai, France, around 1400 and died in 1474. During his lifetime he was a renowned choritser ans choir master at Cambrai Cathedral, as well as being very well-educated in most aspects of music. During his lifetime he was regarded as the premier composer of the 15th century, a title that has stood ever since. He was one of the foremost representatives of the Burgundian school of composition and his contributions to the development of faux-bourdon and the cyclic mass are of particular interest.
Dufay's surviving works consist of seven complete masses, 28 individual Mass movements, 15 settings of chant used in Mass Propers, three Magnificats, two Benidicamus Domino settings, 15 antiphon settings (6 are Marian antiphons), 27 hymns, 22 motets (13 of which are isorhythmic) and 87 chansons.
One of the most popular of Dufay's secular works was the chanson Se le Face ay Pale ("If her face is pale"); this theme was used as a the cantus firmus of his later mass-setting Missa se la face ay pale.
Gillaume Dufay: the man and his music
This link gives an opportunity to hear an extract from Missa se la face ay pale