As far we know and examined in the sources this Missa de Requiem consists out of the following traditional movements:
01. Introito: Requiem aeternam
02. Kyries: Kyrie, Christe, Kyrie
03. Gradual: Requiem Aeternam
04. Secuencia: Dies Irae plainchant
05. Offertorio: Domine Jesus Christe
06. Sanctus: Sanctus y Benedictus
07. Agnus Dei: Agnus Dei
08. Communio: Lux aeterna
This Misa de Requiem a 8 is set by Matias Cardona for double choir in coro spezzato style for SSAT coro I and SATB coro II with figured basso continuo.
From the gradual "Requiem aeternam" only the verse "In memoria aeterna" has been set to music.
In this case contrary to the Misa de Requiem a 4 Cardona sets in the Offertorio the “Domine Jesu Christe” of the sequence "Dies irae" the first four verses have been set to music and the last verses . too as from the verse “Huic ergo”( middle of verse 19).
That means in the performance of the Sequentia you could alternate with the odd verses in coro and some soloists could sing the even plainchant verses.
The score of this Misa de Requiem a 8 consists out of the following parts:
1st chorus treble (4 f.), 1st chorus 2nd treble (4 f.), 1st chorus alto (4 f.), 1st chorus tenor (4 f.), 2nd chorus treble (4 f.), alto 2nd chorus (4 f.), tenor 2nd chorus (4 f.), bass 2nd chorus (4 f.), continuous accompaniment (4 f.), continuous accompaniment (4 f.) This Misa de Requiem is set in the hypo Lydian mode.
This Misa de Requiem a 8 can be found in the Archivo Musical del El Escorial Madrid no 38669 in the Catalogo del Archivo del Monasterio de San Lorenzo El Real de El Escorial page 95 no. 24 ff. 144-182 and page 242 no. 562 en no. 564 and in page 102 no 17 ff 126-133.