Cartimandua

"Treachery" is far too simplistic.  Like any ruler in any time, she was limited by Realpolitik and the need to do all that was possible to retain some sense of autonomy for her tribal confederation in the face of overwhelming odds.  Boudicca would likely have behaved exactly the same had not the Romans stupidly pushed her to the limit.  That she did survive so long in her position despite domestic opposition and outside pressures is testament enough to her strength of character and good political sense.  She had no particular obligation to Caratacus, whose people had most likely been exploiting her northerners for generations (where do you think they got the slaves from to trade with Rome themselves, before Rome decided to take the supply chain into its own hands?).  Sorry, but I just can't allow such casual defamation to go unchallenged!