This French composer was active in Notre Dame, Paris, Sainte-Chapelle, and Chapelle du Roy. Certon predominantly composed masses and motets as well as a magnificat. He is an important figure for his innovations in transforming the chanson. Changes included an increase in the number of voices from four to as many as eight yielding the full extent of the human vocal range. Certon also employed the use of frequent rhythm changes with accents off the major beat. ~ Keith Johnson