In 1768, a young Swedish Lutheran, inspired by Voltaire, took up life as a merchant to learn more about the world and to find “true religion” based upon reason. When he boarded a ship to Corsica, his travelling companions were two hundred Mexican Jesuits recently expelled from the Americas. In close confines with these members of the Society of Jesus for the duration of his five-week journey, Thjülen chose to convert to Catholicism and, shortly after arriving in Italy, he became a Jesuit. This essay explores the nature of his conversion, utilizing affect theory to argue that he converted less to Catholicism than to the Society of Jesus, or—more precisely—Thjülen converted to remain in proximity to a particular Mexican Jesuit named Manuel Mariano (Emmanuele) de Iturriaga.