Post Description

Johannes Ockeghem - Requiem (Missa pro Defunctis), for 3-4 voices (introit, Kyrie, gradual, offertory only)
Johannes Ockeghem's Requiem is a beautiful example of the plainchant mass and is the earliest surviving polyphonic Mass for the Dead. It was most likely written in 1461 and originally consisted of the Introit, Kyrie eleison, Graduale, Tractus, and the Offertorium. All the other texts were probably sung in unembellished plainchant, following normal church practice.

Josquin Desprez - Missa L'Homme Armé super voces musicales, for 4 parts
http://www.allmusic.com/artist/josquin-desprez-mn0001349420

London Pro Cantione Antiqua olv. Bruno Turner
http://www.allmusic.com/artist/pro-cantione-antiqua-mn0002268404