ABSTRACT
This essay aims to analyse a specific range of issues in the period between the time when the orders were brought under the tutelage of the Portuguese Crown and 1773, the date by which the distinction between New Christians and Old Christians had officially been brought to an end. With that in view, it is necessary to outline the prerequisites for admission into the Portuguese military orders and to scrutinize the details and meaning of these requirements in comparison with those of the Castilian orders. Finally, it is crucial to demonstrate the way these prerequisites were ascertained and set them against the procedures followed by other institutions that also had to establish eligibility for membership, such as the Holy Office (Inquisition) in Portugal. In tackling these questions, I shall take into account not only the theoretical framework, which underpins them, but also the actual institutional practices, which are essential for a proper understanding of what was at issue.
