Riothamus, King of Brittany
(Welsh, Riatham/Latin, Riothamus/English, Riathamus)
Riothamus or Riatham, as he was apparently known in Brittany, is remembered as one of the greatest of Breton leaders. Riomathus means Greatest-King. Some historian's, notably Geoffrey Ashe, believe he was the original King Arthur. However, he appears quite clearly in the Breton pedigrees of the Princes of Domnonée recorded in the lives of several saints. He is there recorded as a son Prince Deroch II, though external evidence would suggest he was a son of Prince Deroch I and grandson of Guitol. Like so many Breton princes, Riothamus appears to have been exiled to Britain after his father's death, presumably in the midst of a Civil War.
He eventually returned and killed the usurping general named Marchell. Thus the true Royal Domnonian line was restored. Riothamus may even have been recognised as King of all Brittany.
Riothamus is an historical character well attested in surviving records. A letter from Sidonius Apollinaris, a Roman Prefect and Bishop of Clermont, written around 470, asks Riothamus for justice for "an obscure and humble person," who has had his slaves enticed away, by a group of armed Bretons, for whom the slave-owner was little match. He had appealed to the Bishop who, obviously thought Riothamus a fair-minded enough judge to reprimand his own people.
He is also mentioned in Jordane's 6th century Gothic History. This records how the Roman Emperor Anthemius requested help from the Bretons in fighting the invading Visigoths. Riothamus responded with 12,000 armed men to the aid Roman cause. However, the Roman forces let him down completely and arrived at the ensuing battle too late to prevent the total annihilation of the Breton army at the hands King Euric of the Visigoths.