Postuminus, known to us from his steles found in Rennes in 1969. As indicated by his name, he would have been born under the Flavian dynasty, under the reign of Titus, i.e. between 79 and 81 AD. One of the steles tells us, in Latin, that he took charge over all the public affairs in the Civitas Riedonum. He was twice duumvir and flamen for life for Mars Mullo.
During the Roman era, the strategic position of the town contributed to its importance. To the west the principal Roman route, via Osismii, stretched from Condate to Vorgium (modern Carhaix).
In the year 275, the threat of barbarians led to the erection of a robust brick wall around Rennes. Rennes became known as the "red town".
Threatened by the danger of peasant marauders called bagaudae at the end of the Roman Empire in the 5th century, the Armorican peninsula, including Brittany and therefore Rennes, constituted the last of the strongholds of the western Roman Empire. The invincible Armorican Romans held their ground against Clovis I, who occupied most of Alamans, then the Visigoths. Melaine, the bishop of Rennes, played an important role in the peace treaty between the Franks and the Armoricans in the year 497. He famously declared "Il faut faire la paix entre chrétiens" ("Peace must be made between Christians").
Middle Ages
Starting in the 5th century, Bretons occupied the western part of the Armorican peninsula, which started to be called Little Britain, and then Brittany, while the Franks took the rest of Armorica. To contain the expansion and avoid Breton incursions, the Carolingians instituted a Breton March or frontier province, composed of the counties of Rennes, Nantes, and Vannes. These marches were entirely absorbed by the Breton Kingdom in the 9th century, and Rennes became fully Breton in 851. Rennes would later become the capital of the duchy of Brittany.
During the Breton War of Succession, in 1356 and 1357, the city was laid siege to by
