Rivallo
| Rivallo | |
|---|---|
| King of Britain | |
| Reign | c. 817BCE | 
| Predecessor | Cunedagius | 
| Successor | Gurgustius | 
| Issue | 
 | 
| Father | Cunedagius | 
Rivallo (Welsh: Rhiwallon) was a legendary king of the Britons as accounted by Geoffrey of Monmouth. He came to power in 817BC.
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".
His reign was troubled by natural disasters: a rain of blood that lasted three days, a devastating plague, and a great swarm of flies. He was succeeded by his son Gurgustius.