Rural Gaul was evangelized by Martin of Tours, 1 founder of monasteries at Ligugé and Marmoutier, made famous by Sulpicius Severus' story, mocked by Jerome, of cutting his cloak to give half to a beggar. The Rhine frontier was fortified; but pagan Germans overwhelmed it.
While the eastern churches were engaged in a divisive controversy concerning Christology, the west had different problems. Pope Leo sought and obtained support in Gaul for his Tome and had earlier persuaded John Cassian to write against Nestorius, of whom Cassian knew next to nothing; but, with rare exceptions such as Gennadius of Marseille fluent in Greek who about 470 wrote (lost) works against Nestorius and Eutyches, the Gallic churches were far more disturbed by the consequences of barbarian movements into their territory. Leo also had difficulties when in 445 Hilary, an aristocrat trained in the ascetic life at the idiorrhythmic monastery founded by a noble named Honoratus on the island of Lérins (near Cannes) and an energetic bishop of Arles active in building churches in his city, replaced a bishop of the metropolitan see of Besançon (Vesontio), Chelidonius. He was accused of having married a widow and of having, as a provincial governor (praeses) before ordination, imposed capital punishment. Germanus of Auxerre, whose career from governor to bishop had run closely parallel to that of Chelidonius, was a party to Hilary's action. The deposed bishop had evidently said or done something to give serious offence to Hilary and his network of aristocratic bishops. By custom the bishop of Arles had the right to gather bishops in synod (explicit in canon 18 of a collection ascribed to the second council of Arles, perhaps in or soon after 443; Germanus died