The city of Rome appears in the works of the French naturalist Pierre Belon as a decisive place, one of the main nodes of his multiple trajectories, both geographical and intellectual. Rome is constantly recurring in his writings, in several forms: through the visits he made there, which are reflected in references to Roman spaces and antiquities, as well as through the ancient scholarly tradition, which was mobilized as a source of information on the natural world. This article analyses the role played by the Roman terrain in Belon's project of naturalist knowledge in relation to the Levant, another space he experienced, and which lies at the heart of his texts. If other places, notably Italian as Venice, contribute to Belon's grasp of the Levant, it will be shown that Rome is in this respect a central and singular crossroads, which offers a multiplicity of resources and therefore constitutes a point of entry and anchorage in which several scales and dimensions are at play. We will also try to demonstrate the interest in linking the "Roman" Belon to the place occupied by French politico confessional interests in Rome, by grasping the extent to which his defense of the Catholic Church is linked to his path in the Eastern Mediterranean.