Riothamus was a Romano-Britishmilitary leader, who was active circa AD 470. He fought against the Goths in alliance with the declining Western Roman Empire. He is called "King of the Britons" by the 6th-century historian Jordanes, but the extent of his realm is unclear. Some Arthurian scholars identify Riothamus as one of the possible sources of the legendary King Arthur.
Name
Riothamus is a Latinization of the Brythonic*Rigotamos, meaning 'Great King', 'Kingliest'. Alternately, it may come from Brittonic *Riotamos, meaning 'Freest" The Brittonic form survived into Old Welsh as Riatav and Old BretonRiatam.
Realm
It is not clear whether Jordanes' "Britons" refers to the Britons of Great Britain itself, or of Armorica, which was undergoing significant British settlement and later came to be known as Brittany. The Old Breton name Riatam, which is derived from Brittonic *Rigotamos, appears in medieval Breton records as one of the Princes of Domnonée. He is identified as a son of Deroch II. For chronological reasons, this Riatam is probably a different individual from Jordanes' Riothamus, who lived earlier.
More secure information is provided by a letter which has survived that was written to Riothamus from Sidonius Apollinaris, bishop of Clermont, who requested his judgment for "an obscure and humble person" who had had his slaves enticed away by a group of armed Bretons. According to C.E.V. Nixon, the letter is evidence that Armorica at this time was becoming "like a magnet to peasants, coloni, slaves and the hard-pressed" as Roman power weakened. Poorer subjects of Rome with no stake in land ownership found Breton territory to be a safe haven from the Goths.
The letter
Translation
War with the Goths
Jordanes states that Riothamus supported the Romans against the Visigoths led by Euric. In The Origin and Deeds of the Goths, he states that Riothamus brought a British army to supplement Roman forces but suffered defeat fighting against overwhelming odds when the Goths intercepted his force:
Jordanes, Getica, XLV.237-238
Translation
A letter from Sidonius Apollinaris to his friend Vincentius, written circa 468 AD, records that Roman officials intercepted a letter written by the Praetorian Prefect of Gaul, Arvandus, to the Visigothic king Euric stating that "the Britons stationed beyond the Loire should be attacked" and that the Visigoths and Burgundians should divide Gaul between them; this has led some scholars to suggest that Arvandus betrayed Riothamus. This letter does not mention Riothamus by name, however, and, it is possible that Riothamus and his forces were not the direct subject of Arvandus' message to Euric, as Arvandus was already under arrest and on his way to Rome before Riothamus had even entered the fray against the Visigoths, sometime between 470 and 472 AD.
Riothamus has been identified as a candidate for the historical King Arthur by several scholars over the centuries, notably the popular historianGeoffrey Ashe, primarily due to Riothamus' activities in Gaul, which bear a casual resemblance to King Arthur's Gallic campaign as first recorded by Geoffrey of Monmouth in his fictional Historia Regum Britanniae. Geoffrey Ashe has suggested a link between Riothamus' alleged betrayal by Arvandus and Arthur's betrayal by Mordred in the Historia Regum Britanniae, and proposes that Riothamus' last known position was near the Burgundian town of Avallon, which he suggests is the basis for the Arthurian connection to Avalon. Academic historian Léon Fleuriot argued that Riothamus is identical to Ambrosius Aurelianus, an historical figure in Britain around this time who, in the early narratives containing Arthur, preceded Arthur. Fleuriot suggested that "Riothamus" was Aurelianus' title as overlord of all Brythonic territories. He noted that "Riothamus" and Aurelianus are contemporaneous and that Aurelianus is the only British leader of the time who is identified as ruling both Brythons and Franks, which could only be the case if he ruled territory in Brittany. He also suggested that the name "Abros" in Breton genealogies is a contraction of "Ambrosius" and that Nennius indicates that Ambrosius was supreme ruler of the Britons, which, Fleuriot argues, would translate as "Riothamus". Fleuriot suggested that Ambrosius led the Britons in the battle against the Goths, but then returned to Britain to continue the war against the Saxons.
