A peak in the incredible skill of the polyphonic composers is the famous Tallis Motet Spem in Alium, with 40 individual voices . I quote wiki now:

The motet is laid out for eight choirs of five voices (soprano, alto, tenor, baritone and bass). It is most likely that Tallis intended his singers to stand in a horseshoe shape. Beginning with a single voice from the first choir, other voices join in imitation, each in turn falling silent as the music moves around the eight choirs. All forty voices enter simultaneously 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 for the culmination of the work. Though composed in imitative style and occasionally homophonic, its individual vocal lines act quite freely within its fairly simple harmonic framework, allowing for an astonishing number of individual 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, 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.

The work is not often performed, as it requires at least forty singers capable of meeting its technical demands. The discipline that comes with performing the masterpiece is highlighted in the importance of the conductor and the performers alike. Whilst performers are distributed throughout a venue, the conductor becomes truly the hub for the piece throughout, as often there is little or no visibility between the performers, and a large venue will present acoustical challenges, not regarded with traditional choirs co-located.

 

Listen and look:

 

Version 1: http://www.youtube.com/watch?v=QmH1nZSGIyY

 

Version 2: http://www.youtube.com/watch?v=XJDLQZWKWe8

 

Version 3: http://www.youtube.com/watch?v=P2rK_Yhpui8

 

Version 4: http://www.youtube.com/watch?v=7Cn7ZW8ts3Y

 

And my favourite program that inspired me to do all this work on music: discovering music

http://www.bbc.co.uk/radio3/discoveringmusic/pipassets/ram/cdm0744tallis40.ram

 

A remarkable piece, all different performances, and all with its one colour, its own precious touch. And why do I switch now to a piece composed by an English composer, probably performed in 1573 for Queen Elizabeth? Because this is a highlight, the endpoint in long journey. An achievement never repeated, but definitely impossible without the Flemish school! We might even say that Schütz and Bach are standing on the shoulders of this great musicians!