Pietro Gabrielli was a cleric tried by the Roman Inquisition for being the patron of a group of libertine intellectuals in !&"/. He was sentenced to life detention in the fortress of Perugia. This article analyses his time in prison and describes how he managed to continue his studies with the intellectuals present in Perugia between 1692 and 1704. Gabrielli discussed with Antonio Felice Marsili, Alessandro Burgos and Domenico Lazzarini during this period of time. Therefore, he was in contact with a heterogeneous group of professors and clergymen, that were committed to reform the Universities’ teachings in the Papal States. This article has reconstructed the activities of these intellectuals, describing how they were the branch of a much larger movement, that created a precedent for the successive enlightened reforms.