<p>In the churches of Euskal Herria there exists today a religious institution of great antiquity and one that clearly demonstrates the high status traditionally afforded to the female in Basque culture. The serora, also referred to as sorora, freila, benoîte, benedicta and beata, is a woman who acts as an adjunct to the priest in the ritual activities of the Catholic Church. In the 20th century her continuing presence represents an anachronism and anomaly when viewed in light of repeated decisions by the Catholic hierarchy concerning the officially approved role of women in the Church. The morphology of this institution will be viewed from two perspectives. First, it will be analyzed synchronically as a set of functions or structures constituting the field of activity of the serora. Then, in order to understand the significance of the survival of these functions, a diachronic approach will be utilized to trace their evolution back into the indigenous religious structures and associated patterns of belief. Having established a hypothetical model for the pre-existing morphology of the institution, it will be possible to describe the way in which the earlier set of structures was modified by increasing contact with the forms and contents of Christianity. With the passage of time the formative elements of the indigenous substratum become overlaid and modified by their fusion with Christianity. Nonetheless, as will be demonstrated, the syncretistic processes at work allowed the earlier structures to survive under the guise of what are understood to be Christian rituals and symbols. Thus, the original indigenous patterns continued to function as generative infrastructures latent even in their modern counterparts. In the latter sections of the paper the duties and responsibilities of the serora are compared with those associated with the Beguines and a new etymology of the term “Beguine” is put forward.</p>