Who was Catalina de Erauso, the Lieutenant Nun? Swashbuckler, brawler, hard-headed businessperson, soldier, gallant, celebrity, transvestite, nun? How can one fail to be fascinated by her? A woman, yet a man; a soldier, yet a nun; Spanish, yet Basque. Catalina de Erauso embodied the contradictions and conflicts of the Early Modern Period, but she also transcended them in her own way. She became a stage on which we see how tensions between different identities played out in sixteenth--and seventeenth--century Spain, particularly the tensions between two sexual identities, male and female, and between the competing and multiple national "identities" already defined and being defined within that new thing that was "Spain." This book explores the different facets of Erauso's persona: her sexual identity and the factors that determined her choice of gender roles; and her Basque origin and its impact on her life and her self-image.