The women in the family which ruled 13th-century Castile used maternity, familial and political strategy, and religious and cultural patronage to secure their personal power as well as to promote their lineage. Leonor of England, and her daughters Blanche of Castile (Queen of France), Urraca (Queen of Portugal), Costanza (a Cistercian nun of Las Huelgas) and Leonor, (Queen of Aragon) provide the context for a study focusing on Berenguela of Castile, Queen of Leon through marriage and of Castile by right of inheritance, whose most significant accomplishment was to enable the successful rule of her son Fernando.