Gallo-Roman theologian and the brother of St. Mamertus, Bishop of Vienne (d. about 473)
Claudianus Mamertus (the name Ecdicius is unauthorized) a Gallo-Roman theologian and the brother of St. Mamertus, Bishop of Vienne, d. about 473. Descended probably from one of the leading families of the country, Claudianus Mamertus relinquished his worldly goods and embraced the monastic life. He assisted his brother in the discharge of his functions, and Sidonius Apollinaris describes him as directing the psalm-singing of the chanters, who were formed into groups and chanted alternate verses, whilst the bishop was at the altar celebrating the sacred mysteries. "Psalmorum hie modulator et phonascus ante altaria fratre gratulante instructas docuit sonare classes" (Epist., IV, xi,; V, 13-15). This passage is of importance in the history of liturgical chant. In the same epigram, which constitutes the epitaph of Claudianus Mamertus, Sidonius also informs us that this distinguished scholar composed a lectionary, that is, a collection of readings from Sacred Scripture to be made on the occasion of certain celebrations during the year.
According to the same writer, Claudianus "pierced the sects with the power of eloquence", an allusion to a prose treatise entitled "On the State of the Soul", or "On the Substance of the Soul". Written between468 and 472, this work was destined to combat the ideas of Faustus, Bishop of Reii (Riez, in the department of Basses-Alpes), particularly his thesis on the corporeity of the soul. Plato, whom he perhaps read in Greek, Porphyry, and especially Plotinus and St. Augustine furnished Claudianus with arguments. But his method was decidedly peripatetic and foretokened Scholasticism. Even his language had the same characteristics as that of some of the medieval philosophers: hence Claudianus used many abstract adverbs in ter (essentialiter, accidenter, etc.; forty according to La Broise). On the other hand he revived obsolete words and, in a letter to Sapaudus of Vienne, a rhetorician, sanctioned the imitation of Naevius, Plautus, Varro, and Gracchus. Undoubtedly his only acquaintance with these authors was through the quotations used by grammarians and the adoption of their style by Apuleius, whose works he eagerly studied. Of course this tendency to copy his predecessors led Claudianus to acquire an entirely artificial mode of expression which Sidonius, in wishing to compliment, called a modern antique (Epist., IV, iii, 3). Besides the treatise and the letter to Sapaudus, both of which are of value in the study of the progress of culture in Gaul, we have a letter from Claudianus to Sidonius Apollinaris, found among the letters of the latter (IV, ii). Some poetry has also been ascribed to him, although erroneously. For instance, he has been credited with the "Pange lingua", which is by Venantius Fortunatus (Carm., II, ii); "Contra vanos poetas ad collegam", a poem recommending the choice of Christian subjects and written by Paulinus of Nola (Carm., xxii); two short Latin poems in honor of Christ, one by Claudius Claudianus (Birt ed., p. 330; Koch ed., p. 248) and the other by Merobaudus (Vollmer ed., p. 19), and two other Greek poems on the same subject, believed to be the work of Claudius Claudianus.
Two facts assign Claudianus Mamertus a place in the history of thought: he took part in the reaction against Semipelagianism, which took place in Gaul towards the close of the fifth century and he was the precursor of Scholasticism, forestalling the system of Roscellinus and Abelard. The logical method pursued by Claudianus commanded the esteem and investigation of Berengarius of Tours, Nicholas of Clairvaux, secretary to St. Bernard, and Richard de Fournival.