Letters written by early modern missionaries played an important role in the development of global intellectual networks and inquiry into religion, language, cartography, and science. But the historical ethnography of law has not recognized the role that Jesuits played in creating the field of comparative law. This article examines the writings on law in India by the French Jesuit Jean-Venant Bouchet, who was an important source for Enlightenment philosophes and later Orientalists. It considers Bouchet’s systemic accounts of Indian law alongside his more ethnographic description of his legal encounters in South India, and argues that the practice of conversion and experiences in local legal fora determined and shaped Bouchet’s interpretation of Indian law. In other words, legal scholarship was produced in spiritual, religious, and political contexts, and cannot be abstracted from them.