Camulus or Camulos was a theonym for a deity of the Celts that the Romans equated with Mars in the interpretatio graeca. He was an important god of early Great Britain and Gaul, especially among the Belgae and the Remi, a Gaulish people living in the region that is now modern Grand Est around Reims.
Camulus is named in combination with Mars in inscriptions coming from Reims, Arlon, Kruishoutem, Rindern, Mainz, Bar Hill Fort near the Antonine Wall, Sarmizegetusa and Southwark, London
At Rindern, Germany, Mars Camulos appears on a stone with a wreath of oak. Elsewhere he was portrayed with a ram-horned head. Evidence of his popularity can be seen in several place-names notably Camulodunum. Attempts to link him with the nursery character Old King Cole and Fionn's father Cumhall have been rejected by contemporary scholars.
The town Camulodunum (now Colchester) in Essex may have been named after him, and is the possible basis for the legendary city Camelot. Camulodunum is a Latinised form of the Brittonic Camulodūnon from Camulos plus dūnon "(hill)fort, stronghold", a reference to the town's extensive Iron Age earthwork defences.