A fantasy on the 3-voice organum Alleluia: Nativitas composed by the 12th century master, Perotin. The work uses great blocks of Perotin's polyphony, juxtaposed and superimposed at multiple tempos and embroidered with some new materials echoing the Gothic style. The work was originally written for the North Hills High School Band. 2+Picc.2.3+Eb Clar+BCl+ContraBCl.2.AATB Saxes: 4.4.4.2 Euph.3: Perc(6).Organ/Synth.Pno