When the Romans invaded Britain in AD 43, they found the place being run by various tribal chieftans and kings. For the most part, they allowed them to remain to control their own people, under Roman rule, of course.
Boudicca was the wife of Prasutagus, a king of the East Anglia region. He died, and in his will, he left the kingdom to his daughters as well as the Roman emperor as he was bound to do. But Rome pulled a fast one and tried to take the whole darned thing. To show their might, they publically flogged Boudicca and raped her daughters. She didn't take kindly to this and took up arms and started a rebellion. You do not mess with babes with swords! She led an army some 100,000 men strong, marched on Colchester, London, and St. Albans, slaughtering the 9th Roman Legion. She was eventually routed and was killed around AD 61. But I bet that scared the togas right off those Romans.
Next time: Roman Basilica