Caradoc, if he existed at all, would not have been a king, but probably held some powerful office within the Roman administration of the mid-4th century. He held sway over the Celtic Dumnonii tribe who lived in what is now Cornwall, Devon and Somerset, so perhaps he was decurion of the main population centre in the region, at Isca Dumnoniorum (modern Exeter).

Caradoc is said to have been the trusted advisor of the supposed British 'High-King' (perhaps the Praeses of Britannia Prima) named Octavius the Old (alias Eudaf Hen). He thus became embroiled in many of the political intrigues of the period. It was Caradoc who persuaded Octavius to marry his only daughter to the then Senator, Magnus Maximus (known as Macsen Wledig by the Celtic peoples) and leave him the British High-Kingdom. Though, apparently none of his children survived him, it is possible the Caratacus Stone on Winsford Hill (Somerset) remembers one of his co-lateral descendants: it reads Carataci nepus or "(--------) the descendant of Caradoc".