His enormous surviving musical output -- apparently written in the span of just over 15 years -- comprises 15 "parody" masses, a requiem mass, two complete cycles of Magnificats, over 230 motets, a setting of the 150 psalms in Dutch, and nearly 90 French chansons. His musical style in the masses and motets, like that of his contemporaries Gombert and Willaert
, often lacks the structural clarity for which their immediate predecessor Josquin
was famous; it rather applies the techniques of pervading imitation to achieve a more uniform, seamless, and fluid surface. Often Clemens would extend a musical passage beyond its opening exposition by long sequential repetitions of imitative motives. He also experimented with imitative technique by crafting motives which allow inversion, or "tonal" answers in addition to strict imitation of the original notes. His "parody" masses demonstrate an advance in the infusion of the sections of the mass by a number of different motives from the music of his model. Clemens has also been credited with experimentation in, and propagation of, a "secret chromatic art": a kind of countercultural cryptic notational practice which could only be understood by the initiated among professional musicians (though obviously this is difficult to prove).
One outstanding late achievement of this composer is a complete polyphonic setting of the Dutch Psalter. Martin Luther
's German vernacular translation of the psalms was published in Antwerp in 1534, followed in 1540 by a Dutch translation of the entire Psalter printed by Simon Cock. This volume, the Souterliedekens, listed one popular tune (love songs, drinking songs, ballads, and sacred tunes) for each psalm. Clemens set the entire set in simple, but polished, three-voiced polyphony, usually with the popular tune in the middle voice. His collection, published by Tylman Susato in 1556-1557, differs from the contemporary Geneva Psalter in context as well as musical polish: Calvin's Psalter was intended for public worship, Clemens' for private devotions and social gatherings.