This project sets forth a Mexican American cultural studies treatment of a US Southwestern legend known as the Lady in Blue (La monja azul). The legend is derived from17th-century religious memoriales (accounts) that narrate the miraculous apparition of a living cloistered Spanish nun, Sor María de Agreda, to the Jumano tribe of western New Mexico between the years 1620-1630. However, the Lady in Blue's conversion of the Jumanos was only the first of many recurring appearances she would make in the Americas and Europe over the next three hundred and seventy years. In the American Southwest, northern Mexico and Spain, stories about the apparating nun resurface and are reshaped in response to the demands of their contexts. Her narrative is transatlantic both in terms of what it recounts, and in terms of where it is recounted. She is not only represented on both sides of the ocean, but her portrayal almost always has to do with her being on both side of the ocean. The Lady in Blue narrative brings together dialogues on conquest, both secular and religious, dialogues on the significance of the female body and the feminine written word, and dialogues on the negotiation of space, proximity and identity. Extant research on Lady in Blue focuses on the components of her story as discrete entities, inadvertently divorcing related histories and legends from one another. 20th-century historians have read the account as a medieval holdover in Franciscan mission writing; folklorists as isolated Indo-Hispano accounts; and literary critics as individual anecdotes in twentieth-century literature. In contrast, this dissertation focuses on is the continuity of the narrative-- the way a series of historical figures and documents capture the Lady in Blue as she moves from New Mexico, to Spain, and back to the Franciscan missions of the Southwest, where she is viewed as a proto- or co-missionary. From the missions, the traditions, legends, and folklore about her grew and were contended, resulting in the contemporary dramatic works, novels, short stories and poems about the Lady in Blue. / text