MAMERTUS, bishop of VIENNE, saint. — He is commemorated on May 11. Nothing is known of his life before he became bishop. He was already governing the Church of Vienne in 463, when Pope Hilary had to write to Leontius, bishop of Arles, so that at the annual Synod of Gaul the question of the ordination of the bishop of Die, made by M., might be examined—an ordination that usurped a right belonging to the see of Arles.
In this letter and in another that the same Pope wrote to the bishops of Gaul, M. is described as ambitious, intemperate, proud, rebellious to papal decrees, and threatened with deposition. Sidonius Apollinaris, however,
Avitus, and St. Gregory of Tours praise him as a man of exemplary conduct, of holy life, and zealous for the salvation of souls. M. is renowned in Church history because in 474 he instituted the Rogations (v.) to propitiate God on account of the calamities afflicting his Church. M. died in 475 and was buried in the church of the Apostles outside the walls.