Ockeghem's Requiem, the oldest surviving polyphonic setting of the funeral Mass, is Ockeghem's most famous work, and his most unusual. The style varies widely from movement to movement: the opening Introit, very plain and syllabically set, might have been written in the 1430s by Dufay; the rhapsodic duos in the tract Sicut cervus might have been written 70 years later by Josquin. The chanson "Fors seulement" and the Mass based on it both have a consistently fluid, melodious style and explore very low vocal ranges (as does Brumel's exquisitely gloomy setting of the chanson). The Clerks' Group won a well-deserved Gramophone Award for this disc, the centerpiece of their Ockeghem series. --Matthew Westphal