There exist a range of crusading sources, often well-known texts, that are currently not being as extensively used as they could be. The Cantigas de Santa María, typically read as a devotional text in praise of the Virgin Mary and descriptive of miracles worked through her intercession, is a central document for understanding crusading mentalities in thirteenth-century Castile. This article will examine three particular characteristics – Mary as intercessor, Mary as warrior, and Mary as missionary – to demonstrate one avenue through which the court of Alfonso X of Castile (r. 1252–1284) projected royal ideas about crusading. Even though much of Alfonso X's crusading efforts came to naught, Alfonso's vision, encoded within the Cantigas de Santa María, is a means through which historians can more fully illuminate the rhetoric of crusade in the thirteenth century.