Another vote for Eleanor of Aquitaine
(1122 - 1204)
Incredible woman in any age, but given the times she lived in, makes her 100 times more remarkable still.
She Inherits the duchy of Aquitaine making her one of the richest and most eligible brides in Europe. She marries the King of France (Louis VII), gives birth to two daughters ... divorces him, then marries Henry of Anjou who just happens to be the next King of England and one of the great ones too,(Henry II) who was 11 years younger than her at just 19 - she was 30 at the time.
That didn't stop her bearing him eight children - 5 sons and three daughters - 7 of whom survived to adulthood, one of whom went on to become King Richard the Lionheart, and the other, the infamous King John, making her wife of two kings and mother of two more!
She helped rule Henry II's vast empire, conspired against him with her sons, was imprisoned by him, outlived her younger husband and several of her children, dying at the ripe old age of 82 which was practically unheard of back in those times.
She was also, by all contemporary accounts, stunningly beautiful, could ride and rule like a man and could probably have fought like one too, had she been called upon to do so. She was educated to a level far beyond most women (even the wealthy and powerful ones of the day), spoke several languages, was articulate, clever and politically savvy.