The project aims to re-examine the formative years of Gian Pietro Carafa’s (the future pope Paul IV, 1555-59); specifically his diplomatic missions to England and Spain in the 1510s. Its objective is to reconstruct the relations Carafa enjoyed with the sovereigns Henry VIII and Charles V and their courts and determine the importance of these experiences for his later political and religious choices. In fact, in the 1530s the English king drew Carafa into the troubled affair of his divorce from Catherine of Aragon, while Carafa continued to show an unflinching hostility to Charles V and his son Phillip II which led to the unsuccessful war he unleashed against the Spanish King during his pontificate. In addition, it was in Spain that Carafa became familiar with the workings of the Spanish inquisitorial tribunal. My research intends to find out whether this institution later served as a model for the foundation of the tribunal of the Roman Inquisition which Carafa used to further his programme of intransigent and repressive reform. The project will also dwell on the reception Carafa was given by humanist milieus in northern Europe, particularly by Erasmus with whom Carafa had a controversial relationship that began with his initial acceptance of the former’s Christian humanism and philological projects for the Scriptures and ended with the Opera omnia Erasmi being included on the Index of Prohibited Books under Paul IV’s own pontificate. From this perspective the project also plans to study Carafa’s private correspondence to gain an insight into his personality, one that was apt to change according to demands of political expediency. The study of these aspects will culminate in a historiographical analysis of the conceptual categories of the Catholic Reformation and Counter-Reformation to determine whether their existed within the Church of Rome a drive for repressive reform that had taken shape around the figure of Carafa long before the Council of Trent (1545-63).