Recent scholarship has shown that, even at the heart of the Catholic world, defining holiness in the Counter-Reformation was remarkably difficult, in spite of ongoing Roman reforms meant to centralize and standardize the authentication of saints and relics. If the standards for evaluating sanctity were complex and contested in Rome, they were even less clear to regional actors, such as the Bishop of Jaén, who supervised the discovery of relics in Arjona, a southern Spanish town, beginning in 1628. The new relics presented the bishop, Cardinal Baltasar de Moscoso y Sandoval, with knotty historical, theological, and procedural dilemmas. As such, the Arjona case offers a particularly vivid example of the ambiguities that continued to complicate the assessment of holiness in the early modern period. As the Bishop of Jaén found, the authentication of relics came to involve deeper questions about the nature of theological and historical truth that were unresolved in Counter-Reformation theory and practice.