Spanish demography was permanently altered when Los Reyes Católicos expelled all Jewish inhabitants from Castile in 1492. Earlier that same year, the last vestiges of Muslim power had disappeared with the full political absorption of Andalusia into the Crown of Castile. Only ostensibly willing converts (conversos) remained, yet both conversos and moriscos – Muslims converts to Christianity, following a similar edict in 1502 – projected façades masking attempts to maintain inherited traditions when faced by growing cultural and religious homogeneity. The interaction between Castilian faith communities, both prior to and following 1492, has been the subject of in-depth and, at times, controversial debate for decades, following the mid-twentieth-century introduction of the term ‘convivencia' by the Spanish scholar Castro. Since then, study addressing interaction between relevant groups in Castile – Old Christians, conversos and moriscos – has largely failed to take account of the specific ways in which women met each other, as well as often neglecting to include analysis of the varied slave population, although Castile's trade in slaves increased, creating a class of people who were both disempowered and stripped of their identities. This thesis is the first full Anglophone study to examine relationships between women of differing faiths in Castile; it employs an interdisciplinary approach to the subject informed by theoretical frameworks grounded in feminist, women's and gender history, social anthropology and identity studies, as well as the histories of peoples oppressed on religious and racial grounds. Most women's roles remained the same – they were defined by their relationships to men, cared for their families and tended their homes – yet analysis here shows how the forced intimacy of such a setting highlights the dissimilarities of social status and lineage, while also paradoxically blurring those differences through the shared lives of its inhabitants. Primary sources that situate this analysis not only within a matrix of interfaith relationships, but also illuminate the distinctly female discourses inherent to their construction, include Inquisitorial records, wills and letters of manumission from cities in Castile-La Mancha and Andalusia, adjoining regions within the Crown of Castile, which describe events between the years 1440 and 1571. The author's aim is to furnish the reader with an original approach to the intersection of social relationships, religious beliefs, ethnic identities and gender expectations in late mediaeval and early modern Castile, through which she might view extant evidence of an ongoing climate of fluid identity in response to the imposition of external regulations and a societal structure centred on the household as its basic unit of economy and relationship. What results are memorable profiles of women whose ethnicities, faiths and classes differed and the situations in which they interacted with each other, both inside of and outwith their homes, but always within hierarchies of power predicated on such differences.