Ok, here's a few thoughts:
Alfred the Great- King of Wessex who defended his kingdom by the skin of his teeth, and pretty much saved England from becoming "Daneland"- he could take a lot of credit for creating, or ensuring the survival of, England. He was also said to be quite a wise, sharp and intelligent character, religious, and promoted education through the chruch's. Quite an interesting and enlightend character.
Boudicca- After the Romans raped her three daughters, she triggered a huge rebellion across Britain, leading an army on a bloody rampage which destroyed two or maybe three Roman cities before she was eventually defeated and later commited suicide. To do all that, she must have been of remarkable character.
Aristotle- Studied pretty much everything, tutored Alexander the Great, devised Virtue Ethics, a theory which i am quite fond off, left lots of interesting ideas behind. His influense in Arabic and Western thought has been huge. He is, of course, also connected to Plato and Socraties.
The Emperor Constantine- If this Emperor had not converted to Christanity, or indeed favoured it then i doubt Christanity would still exist today. I would love to find out why (or indeed if he honestly did...) convert to Christanity.