Rivallo (Welsh: Rhiwallon) was a legendary king of the Britons as accounted by Geoffrey of Monmouth. He was the son of King Cunedagius and was noted as a young king who reigned with moderation. Geoffrey describes him as a "peaceful and fortunate youth, who ruled the kingdom well".[1]

His reign was troubled by natural disasters: a rain of blood that lasted three days, a devastating plague, and a great swarm of flies.[1] He was succeeded by his son Gurgustius.


  1. ^ a b Geoffrey of Monmouth: The History of the Kings of Britain : an Edition and Translation of De Gestis Britonum (Historia Regum Britanniae), Boydell & Brewer, 1 Jan 2007, p.44.
Legendary titles
Preceded by King of Britain Succeeded by