Queen Boudicca of the Iceni was a Fianna of Roman Britain. In 61 C.E., she was publicly flogged by Roman legionnaires and forced to watch as her daughters are raped. She underwent her First Change and raised an army against the Romans, who were backed by the Wyrm. Despite victories against Rome, she was eventually defeated and committed suicide.
Boudicca is based on a real person. Please see Wikipedia:Boudicca for more information.