He was the son of a Celtic king named Cunobeline and ruled Briton from 43-50 AD.  Caractacus is associated with the expansion of his tribe's territory with his apparent success being a catalyst for the Roman invasion of Britain.  When the Romans launched their invasion in the summer of 43 AD they attempted to absorb it into the Roman empire.  While other tribes in Britain, such as the Dobunni, submitted to the Romans, Caractacus fought fiercely for the independence of his people.

When the Emperor Claudius launched an invasion of Britain, it was a massive undertaking and intervention which would ultimately lead to more than 350 years of Roman control.  Four legions supported by auxiliary troops made up an invasion force of more than 40,000 men.  Despite what must have seemed like overwhelming Roman strength, there was strong native resistance.