Tamar of Georgia, 1160-1213
Tamar of Georgia was born a princess but her father, King George III, recognized her fierce intelligence and allowed her to co-rule as Heir Apparent. After his death, she took over the crown, suppressing the aristocratic opposition to a female King (yes, that's right: she insisted on being called King, not Queen, because she knew the latter title had less power). She led the Georgian army into battle, protecting its national borders against invasion and single-handedly ushering in the "Golden Age" of Georgian history. Her final insult to the aristocracy was protecting her country's peasant population against royal abuse. Take that, snobs!