Related to the poet Sidonius Apollinaris, bishop of Clermont, Avitus belonged to a family of the great patrician aristocracy. Born in Vienne (Isère) around 450, of Christian parents, he was baptized by Bishop Mamertus, to whom he was (after his father) the successor, from about 490 until his death (518). He was effectively the Bishop of the Burgundian kingdom and its link to the papacy. A defender of the Catholic faith against Arianism, he failed to bring King Gundobad back to orthodoxy. He was nevertheless an influential advisor to the king, whose son Sigismund he succeeded in converting.