Older reference works tend to favour the spelling "Caractacus", coins minted during his rule show the beginning of his name CARA' on the obverse, but some modern scholars agree, based on historical linguistics and source criticism, that the original Common Brittonic form was *Karatākos, pronounced [karaˈtaːkos], cognate with Welsh Caradog, Breton Karadeg, and Irish Carthach, meaning "loving, beloved, dear; friend".

[2] Based on coin distribution Caratacus appears to have been the protégé of his uncle Epaticcus, who expanded Catuvellaunian power westwards most likely from his palace in Verulam, the heartland of the Catuvellauni, into the territory of the Atrebates.

Caratacus and his brother Togodumnus led the initial defence of the country against Aulus Plautius's four legions, thought to have been around 40,000 men, primarily using guerrilla tactics.

Dio reports that Togodumnus was killed (although both Miles Russell and John Hind argue that Dio was mistaken in reporting Togodumnus' death, that he was defeated but survived and was later appointed by the Romans as a friendly king over a number of territories, becoming the loyal king referred to by Tacitus as Cogidubnus or Togidubnus)[7][8] and the Romans conquered the Catuvellaunian territories.

[4][9][10] We next hear of Caratacus in Tacitus's Annals, leading the Silures and Ordovices of Wales against Plautius' successor as governor, Publius Ostorius Scapula.

Caratacus himself escaped and fled north to the lands of the Brigantes (modern Yorkshire), where the Brigantian queen, Cartimandua, handed him over to the Romans in chains.

[12] Legends place Caratacus' last stand at either Caer Caradoc[13] near Church Stretton or British Camp[14] in the Malvern Hills, but the description of Tacitus makes either unlikely: [Caratacus] resorted to the ultimate hazard, adopting a place for battle so that entry, exit, everything would be unfavourable to us and for the better to his own men, with steep mountains all around, and, wherever a gentle access was possible, he strewed rocks in front in the manner of a rampart.

Bari Jones, in Archaeology Today in 1998, identified Blodwel Rocks at Llanymynech in Powys as representing a close fit with Tacitus' account.

Tacitus records a version of his speech in which he says that his stubborn resistance made Rome's glory in defeating him all the greater: If the degree of my nobility and fortune had been matched by moderation in success, I would have come to this City as a friend rather than a captive, nor would you have disdained to receive with a treaty of peace one sprung from brilliant ancestors and commanding a great many nations.

He appears in the Mabinogion as a son of Bran the Blessed, who is left in charge of Britain while his father makes war in Ireland, but is overthrown by Caswallawn (the historical Cassivellaunus, who lived a century earlier than Caratacus).

An 18th-century tradition, popularised by the Welsh antiquarian and forger Iolo Morganwg, credits Caradog, on his return from imprisonment in Rome, with the introduction of Christianity to Britain.

In his days many of the Cymry embraced the faith in Christ through the teaching of the saints of Cor-Eurgain, and many godly men from the countries of Greece and Rome were in Cambria.

[26] One is Pomponia Graecina, wife of Aulus Plautius, the conqueror of Britain, who as Tacitus relates, was accused of following a "foreign superstition", which the tradition considers to be Christianity.

It has been argued since the 17th century[31] that this pair may be the same as the Claudia and Pudens mentioned as members of the Roman Christian community in 2 Timothy in the New Testament.