Boudica, or Boudicea, or Boudicca, whichever you prefer, was the queen of a tribe called the Iceni, an ancient Celtic group. When the scurrilous Roman's invaded England, they reputedly attacked Boudica, whose husband had recently died, and raped her daughters, instigating a full throttle revenge attack which would bring the Roman rule of Britain almost to its knees.
Boudica created an army and took the capital city of Londinium by force, razing it to the ground. Even now, a layer of ash an inch thick lies beneath our streets. She also held the important Roman city of Verulamium, now St Albans. The Roman's regained the upper hand in the Midlands, defeating her at the Battle of Watling Street, after which, Boudica died.
It's not clear whether she committed suicide or died of natural causes, but her rebellion died with her, and England returned to Roman rule. She was buried around about platform 9 at the modern day Kings Cross Station.
For more on Boudica and the Romans, see our blog What did the Romans ever do for us?.