The Commonitorium and the Vincentian Canon
Written under the name Peregrinus, the Commonitorium was an apologetic guide for distinguishing authentic catholic doctrine from heresy by appeal to Scripture and the consenting witness of the Church. Its best-known passage holds to the faith that has been believed everywhere, always, and by all, a threefold test of universality, antiquity, and consent: doctrines received across the whole Church, maintained from the earliest times, and acknowledged by the recognized authorities of the Church.
Vincent also addressed how teaching may legitimately deepen over time. He held that genuine development is permissible when it represents progress rather than alteration, so that the same faith may be expressed in a new way while the deposit handed down is preserved intact, with the decrees of universal councils taking precedence. The treatise originally comprised two parts; the second was lost during Vincent's lifetime, and he supplied a synopsis rather than rewriting it.