What is "fauxbourdon"

Fauxbourdon (also Fauxbordon, and also commonly two words: Faux bourdon or Faulx bourdon) – French for false bass – is a technique of musical harmonisation used in the late Middle Ages and early Renaissance, particularly by composers of the Burgundian School. Guillaume Dufay was a prominent practitioner of the form (as was John Dunstaple), and may have been its inventor. The homophony and mostly parallel harmony allows the text of the mostly liturgical lyrics to be understood clearly.