Rarely performed due to it's complexity, it demands eight five voice choirs normally arranged in horeshoe, to begin singing and gradually increase to a point where all forty voices are singing and replying to each other to the point where at times I believe every voice is singing a different refrain. The wikipedia entry on the pieces quality is worth quoting in full, in order to grasp exactly what Tallis achieved.
Now go listen.The motet is laid out for eight choirs of five voices [soprano, alto, tenor, baritone and bass]...stand[ing] in a horseshoe shape. Beginning with a single voice from the first choir, the other voices join in imitation, each in turn falling silent as the music moves around the eight choirs. All forty voices enter for a few bars, and then the pattern of the opening is reversed with the music passing from choir eight to choir one. There is another brief full section after which the choirs sing in antiphonal pairs throwing the sound across the space between them. Finally all voices join in the culmination of the work. Though composed in imitative style and occasionally homophonic, it's individual voice-lines act quite freely within its elegent harmonic framework, allowing for an astonishing number of musical ideas to be sung during its ten to twelve minute performance time. The work is a study in contrasts; the individual voices sing and are silent in turns, sometimes alone and sometimes in choirs, sometimes calling and answering, sometimes all together, so that far from being a monotonous mess, the work is continually presenting new ideas.
Enjoy; Peter.
