“You will never again be my slave, but my true Brother.”

The Society of Jesus emerged in a historical context in which Islam was still perceived as a threat in Europe and the Mediterranean. Despite the fall of the Emirate of Granada in 1492, Muslims and Moriscos continued to represent a significant presence. This context is reflected even in the autobiography of Ignatius of Loyola, which recounts an encounter with a Muslim that provoked a violent internal crisis. Against this backdrop, the study focuses on the exceptional case of Baldassarre, a former Muslim who, after converting to Catholicism, entered the Society of Jesus and left behind a rich body of documentation concerning his experiences. His writings provide an exceptional source for analyzing Catholic perceptions of Islam during the early modern period, as well as the living conditions of enslaved Muslims. In particular, four texts are examined that illustrate a progression from an initial phase influenced by Islamic elements to a more explicit adoption of anti-Islamic rhetoric, consistent with the religious conversion strategies developed in the Mediterranean during the seventeenth century.