ABSTRACT This paper focuses on Giovanni Antonio Costanzi, a converted Jew in the service of the Holy Office. Primary sources, including his writings and documents related to his service in the Roman Inquisition, form the foundation of our study, supplemented by secondary sources from ecclesiastical archives. These materials allow us to reconstruct aspects of Costanzi’s life, comprehend his involvement with the Holy Office, and explore his potential contributions to Anna del Monte’s Diary. Building upon previous research, the aim is to present new data, establishing a revised chronology for Costanzi and shedding light on his role within a broader historical context. As individuals straddling two worlds, converts occupied a precarious position, continually striving to demonstrate their loyalty to Christianity. The paper includes an appendix that details Costanzi’s direct involvement in the conversion of Jews, revealing the intricate dynamics of this period.

issue 24 / n.2 (2023) by Miriam Benfatto