This is the first modern scholarly biography of Blanche of Castile, whose identity has until now been subsumed in that of her son, the saintly Louis IX. A central figure in the politics of medieval Europe, Blanche was a sophisticated patron of religion and culture. Through Lindy Grant’s engaging account, based on a close analysis of Blanche’s household accounts and of the social and religious networks on which her power and agency depended, Blanche is revealed as a vibrant and intellectually questioning personality.