Riothamus (also spelled Riutimus or Riotimus) was a Romano-British military leader, who was active circa AD 470. He fought against the Goths in alliance with the declining Roman Empire. He is called "King of the Britons" by the 6th-century historian Jordanes, but the extent of his realm is unclear. Riothamus is a Latinization of the Brythonic personal name *Rigotamos, meaning 'king-most', 'supreme king' or 'highest king'. Though it is still a matter of debate, several scholars consider his life to have been one of the possible sources for the King Arthur legend.