In the early Middle Ages when Britain consisted of numerous petty kingdoms, the concept of one ruler ‘paying homage to’ (acknowledging the superiority of) another was an important one. It served two purposes: that of allowing a less powerful leader to continue in his role; and reassuring the more powerful leader that no attempt would be made to usurp his authority. In the 10th century, Hywel Dda, King of Deheubarth, paid homage to both Edward the Elder of England and his son Athelstan.
The name Caswallon is thought to be a version of Cassivellaunos, who is said to have fought against Julius Caesar and his forces when they invaded Britain in 54 BC.
The name Beli has been connected with that of Bel or Belenus, the Celtic sun god, who in Roman times was equated with Apollo. Alternatively, the name may have some connection with Belgius, a Gaulish leader of the 3rd century BC.