About Cartismandua . ., Queen of the Brigantes
She is NOT the wife or daughter of any of these: Caractacus/Caradoc/Arvigarus, Bodiccea and Prasutagus, St. Cyllin/Marius, King of Briton, or Bran the Blessed.
Cartismandua was queen of the Brigantes tribe of northern Britain at the time of the Roman invasion in 43AD. Cartismandua initially supported the Romans in exchange for being allowed to maintain control of her lands - a practice known as "client-kingship".
In 51 AD Caratacus, leader of the British resistance to the Romans, fled to Cartismandua for support. However, she betrayed him to the Romans, thus depriving Celtic Britain of its most influential and steadfast military leader.
This was a fairly typical act for the Celts, who could never stop fighting amongst themselves long enough to mount a serious obstacle to the Roman advance. But it also indicates the extent to which Cartismandua owed her continued power to her alliance with the Romans.
Cartismandua soon had cause to be grateful to her Roman allies; in 57 AD her husband Venutius tried to oust her and sieze power for himself, but the Romans put down the rebellion. The couple were reconciled for a time and ruled jointly until 69 AD, when Cartismandua deserted her husband Venetius for his armour-bearer, Vellocatus. She fled Brigantine territory and was never heard from again.