Gennadius of Massilia's De viris illustribus (lxxxiv, 89) repeats the tradition that Prosper dictated the famous letters of Leo I against Eutyches.

The theme, dogma quod ... pestifero vomuit coluber sermone Britannus, is relieved by a treatment not lacking in liveliness and in classical measures.

He also induced Pope Celestine to publish an open letter to the bishops of Gaul, Epistola ad episcopos Gallorum against some members of the Gaulish Church.

He had earlier opened a correspondence with Augustine, along with his friend Hilary (not Hilary of Arles), and although he did not meet him personally, his enthusiasm for the great theologian led him to make an abridgment of his commentary on the Psalms, as well as a collection of sentences from his works—probably the first dogmatic compilation of that class in which Peter Lombard's Liber sententiarum is the best-known example.

[6] The Encyclopædia Britannica 1911 found it a careless compilation from Jerome in the earlier part, and from other writers in the later,[7] but that the lack of other sources makes it very valuable for the period from 425 to 455, which is drawn from Prosper's personal experience.

This was Prosper's attempt to reconcile Augustine of Hippo's teaching on grace in which he suggests that God wishes all men to be saved.

This was a simple list of ten doctrinal points asserting the efficacy and necessity of God's Grace, each separately supported by papal statements.

The motto of the florilegia was monastically influenced, urging the reader to patience through adversity, exercise of virtue, and constant striving to perfection.

It was written during the reign of Pope Sixtus III (link) and is a step-by step response to Conference XIII of the Conlationes of John Cassian.

[12] The problem of providence is discussed in the context of God's creation of the World and in relation to the invasion of Gaul by the Vandals and the Goths.

(Abbé L. Valentin) However, many historians believe his chief fame rests not on his historical work, but on his activities as a theologian and an aggressive propagator of the Augustinian doctrine of grace.

Prosper's epigrams became most popular in his later years, providing a method for students of Christianity to learn moral lessons and aspects of the Augustinian doctrine.

Prosper's Epitoma Chronicon was edited by Theodor Mommsen in the Chronica minora of the Monumenta Germaniae Historica (1892) and by Maria Becker and Jan–Markus Kötter as part of the Kleine und fragmentarische Historiker (KFHist G 5) (2016).