Avitus, as metropolitan of southern and eastern Gaul, took the lead in a conference between the Catholic and Arian bishops held in presence of Gundobad at Sardiniacum near Lyons.

A letter of Pope Hormisdas to Avitus[11] records that he was made vicar apostolic in Gaul by that pontiff; and in 517 he presided in this capacity at the Council of Epaon for restoring ecclesiastical discipline in Gallia Narbonensis.

Avitus appears also to have exerted himself to terminate the dispute between the churches of Rome and Constantinople which arose out of the excommunication of Acacius; his later letters suggest that this was accomplished before his death.

The literary fame of Avitus rests on his many surviving letters (his recent editors make them ninety-six in all)[13] and on a long poem, Poematum de Mosaicae historiae gestis (also known as De spiritualis historiae gestis), in classical hexameters, in five books, dealing with the Biblical themes of original sin, expulsion from Paradise, the Deluge, and the Crossing of the Red Sea.

Like his contemporary, Ennodius of Pavia, he was strenuous in his assertion of the authority of the Apostolic See as the chief bulwark of religious unity and the incipient Christian civilization.

"If the pope," he says, "is rejected, it follows that not one bishop, the whole episcopate threatens to fall" (Si papa urbis vocatur in dubium, episcopatus videbitur, non episcopus, vaccilare.

[7] The so-called Dialogues with King Gundobad, written to defend the Catholic faith against the Arians and which purports to represent the famous Colloquy of Lyon in 449, was once believed to be his work.

Julien Havet demonstrated in 1885, however, that it is a forgery of the Oratorian, Jérôme Vignier, who also forged a letter purporting to be from Pope Symmachus to Avitus.