MISSA PROLATIONUM

Four-voicedmassofJohannes Ockeghemconstructed as a series ofcanonsprogressing from the unison to the octave in which the four voices sing the same melody at different speeds.Prolationum(Lat. "prolation") refers to the ratio of durations between two kinds of written note, the semibreve and the minim. The mass requires a bit over half an hour to sing.