Aged unknown

Cassivellaunus was a historical British tribal chief who led the defence against Julius Caesar's second expedition to Britain in 54 BC. He led an alliance of tribes against Roman forces, but eventually surrendered after his location was revealed to Julius Caesar by defeated Britons. Cassivellaunus made an impact on the British consciousness. He appears in British legend as Cassibelanus, one of Geoffrey of Monmouth's kings of Britain, and in the Mabinogion, the Brut y Brenhinedd and the Welsh Triads as Caswallawn, son of Beli Mawr. His name in Common Brittonic, *Cassiuellaunos, comes from Proto-Celtic *kassi- "passion, love, hate" (alternately, "long hair", or "bronze") + *uelna-mon- "leader, sovereign".

Wikidata Wikipedia

Commemorated on 2 plaques

Matt Brown on Flickr
Colin Riegels on Wikimedia Commons

BC 51. At this ancient fortified fort tribesmen under Cassivellaunus bravely opposed Julius Caesar on his march to Verulamium

Brentford High Street, London, United Kingdom where they fought

The entrenchment is part of a British city built in the 1st century BC. It was probably here that Julius Caesar defeated the British king Cassivellaunus in 54 BC

Devil's Dyke, Wheathampstead, United Kingdom where they lived and fought