This was an important musical establishment at the time, and several famous composers either worked there or trained there, including Gilles Binchois, who was probably an associate of Regis.
Like his exact contemporary, Johannes Ockeghem, Regis liked to explore the low vocal register resulting in a very broad registral palette, and his music also evidences great harmonic and textural variety.
Two masses, seven motets, and two secular songs, both rondeaux, by Regis have survived; some other music is mentioned by Tinctoris and other writers but is lost.
In addition to this lost mass, he wrote another based on the same tune, a Dum sacrum mysterium/Missa l'homme armé; this one has survived, and is a contrapuntal tour-de-force which uses up to three pre-existing melodies simultaneously in the four voices.
Indeed, his motets for five voices seem to have been used by the next generation, including Loyset Compère, Gaspar van Weerbeke, Josquin, and Jacob Obrecht as models for their own work.