Blanche of Castile

Granddaughter of Henry II of England and Eleanor of Aquitaine, married into the Capetian house at twelve as part of a peace settlement between her grandfather and Philip Augustus. After Louis VIII's sudden death she became regent for her twelve-year-old son and crushed the baronial revolt that immediately broke out, holding the kingdom together by sheer force of personality. She remained the dominant influence on Louis IX's reign even after he came of age, governing France again during his crusade.