Eccard, Johannes: Missa a 5 vocibus (Carus-Verlag)

John Taverner: Missa Sancti Wilhelmi devotio (Alfred/Kalmus)
Taverner's Missa Mater Christi, which is scored for SSABB, may also work for
you depending on your tenor(s).

Orlando di Lassus: Missa paschalis (Novello)

Tomás Luis de Victoria: Missa Ascendens Christus In Altum
Index of /scores/victoria/MissaAscendens

Giovanni Pierluigi da Palestrina: Missa Brevis (starts out SATB, last movement
adds 2nd soprano voice) (Carus-Verlag)
Choir MIDI Learning Files - Palestrina Missa Brevis

Jacob Clemens non Papa: Missa Pastores quidnam vidistis (final movement
adds 2nd bass voice) (privately published by Dr. Bernd Christoph Becker,
Marzellenstraße 62-64 D-50668 Köln, Germany)

--- In theVocalist "Matt"* wrote:

Does anyone know of a Renaissance or EARLY Baroque Mass for SSATB?
Byrd's Mass for five I know is SATTB and wouldn't work with this ensemble.
Most Renaissance composers are known for being very prolific, especially in the
mass category. There has to be an SSATB mass out there, I just have not been
able to find one. If anyone could point me to a mass or publisher I would
GREATLY appreciate it! Thanks!