Blanche of Castile (bläNsh, kăstēlˈ) [key], 1185?–1252, queen of Louis VIII of France and regent during the minority (1226–34) of their son Louis IX. A forceful and capable ruler, she checked the coalitions of the great lords and frustrated the attempt (1230) of Henry III of England to regain his father's lands in France. She remained a lifelong adviser to Louis IX, was again regent on his departure (1248) for the Holy Land, and was coregent with her son Alphonse from 1250 until her death.
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