This Requiem written for 4-5 voices (C)TTBB or (C)TBBB contains:
01. Introitus: Requiem aeternam
02. Kyrie Christe Kyrie
03. Psalmus/Tractus: Sicut cervus
04. Offertorium: Domine Jesu Christe
05. Sanctus
06. Benedictus
07. Angus Dei I, II, III
08. Communio: Lux aeterna
If we see the original mode of the Requiem by De la Rue (See the edition by Michael Procter 2004) we hear and see a work kept in darkly glowing colours. In general this splendid work breaths rich textures and sombre atmospheres with dark colour due to the use of very deep writing in the Bass up to contra-B-flat in Introitus. Now and then is this dark sphere interrupted by characteristic De la Rue fingerprints in the form of really elegant two voice sections, duo-style. This Requiem mass, more than many others, emphasizes the low registers of men voices, and even the lowest voices themselves.This Missa pro fidelibus defunctis is firmly based on the plainchant melodies of the old Gregorian Missa pro Defunctis in a period the liturgical and musical tradition of a Requiem Mass was not yet unified fixed in the Proper and a Ordinary part. Nevertheless De la Rue composed a complete Requiem plenarium, see the content as stated above here. This version was used in the region of Malines. Probably this Requiem was composed for the Death of Philip the Fair, De la Rue’s patron († 1506). Pierre de la Rue was the favourite court-composer in that time, see for instance three Laments De la Rue composed on occasion of the Death of Philip. The used plainchant by De la Rue provides a basis for the polyphonic composition and is integrated as a soberly paraphrased cantus-firmus in the Tenor part, or in a shared paraphrase between Tenor and Discantus. De la Rue uses in Introitus, Offertorium, Sanctus, Benedictus, Agnus Dei and Communio a part of the plainchant to start with, excluded the Kyrie and the Tractus/Psalmus.
In our days the Sicut cervus is no more in use in the Office of the Dead. But many composers used this Proper-section as part of a Requiem-setting, like Johannes Ockeghem (c.1420-1497), Pedro de Escobar (c.1465-aft.1535), Antoine de Févin (1473-1512), Benedictus Appenzeller (c.1480/88-aft.1558). All parts of this Requiem are in principal written for four voices excluded the Kyrie III, Quam Olim Abrahae, Sanctus, Osanna, Agnus Dei I, II, III. These parts are written for five voices. The beginning of the Sicut cervus (bar 1 up to 34) like the beginning of the Offertorium ( bar 1 up to 40) are written in an real elegant way for two voices. In fact a real duo in a De la Rue style. And see at last the middle of the Offertorium after Hostias, the Tu suscipe (bar 77 up to 85) written in the same duo-style.
This Missa pro fidelibus defunctis is among others three times found in the famous Codex of Munich which was carried off by Swedish in 1631 and further edited in other sources like Jena, Thüringer Universitäts- und Landesbibliothek, MS 12, Origin: in Brussels/Malines,1508-1525; Vatican City, Biblioteca Apostolica Vaticana, MS Cappella Sistina 36, Origin in Brussels/Malines, 1513-1518.
His requiem is a work of sombre gravity, exploiting low vocal registers, and his chansons are sober and frequently sad --especially those written under the patronage of the ill-fated Marguerite--with continuous textures and imitative writing.