Although there is an established historiography on women’s roles during the Spanish Civil War (1936-9), little has been written on Nationalist women in the Republican-held zones. Women were the anti-Republican resisters of the first hour in the capital but they have been largely overlooked in the historical record. During the bitter civil conflict a sector of dissident women helped to create a subversive and clandestine national Catholic space in the heart of Republican Madrid. By examining the vital and invisible role played by women within Madrid’s ‘fifth column’ this monograph offers a new contribution to the gender historiography of the Spanish Civil War and re-evaluates the significance of women in the Nationalist war effort. It explores how and why a sector of Falangist and Catholic women decided to mobilise against the legally constituted Popular Front government in support of an undemocratic military coup. While women’s subversive activities often involved the transgression of traditional gender norms, their social and political agency arose within the conditions and precepts of Catholicism and was conceptualised and imagined within new national-Catholic discourses of ‘holy Crusade.’