In the chronicles, the King of Britain during Julius Caesar’s invasion in the first century BC. He ascended to the throne of Britain after the death of his brother, King Lud, whose sons were too young to receive the crown. Cassibelaunus was a magnanimous ruler; though he retained the throne when his nephews came of age, he invested them with lands and cities.
Julius Caesar demanded Cassibelaunus’s fealty and invaded when Cassibelaunus refused. Cassibelaunus enjoyed several victories against Caesar before his nephew, Duke Androgeus of London and Kent, rebelled against him and joined Caesar’s forces. Caesar conquered Britain but was pursuaded to leave Cassibelaunus on the throne provided the later pay an annual tribune to Rome.
Cassibelaunus ruled for seven more years, died, and was succeeded by his other nephew, Duke Tenuantius of Cornwall. In the Short Metrical Chronicle, the chronology of which is confused, Cassibelaunus is succeeded by Uther Pendragon.
Historia Regum Britanniae | Geoffrey of Monmouth, c. 1138
Roman de Brut | Wace, c. 1155
Short Metrical Chronicle | 1307