This article combines ethnographic description of the practices of Hindu and Christian visitors of the St. Antony Shrine in Chennai with the observation that this material cannot be understood using the standard world religions paradigm that essentializes Christianity as exclusivistic. Drawing upon the visual and material culture of the shrine in light of premodern and Vatican II templates for inculturation and the negotiation of religious difference, the article highlights overlap between Tamil Hinduism and the Tamil Popular Catholicism of the site to argue that the beliefs and practices documented should inform descriptive and normative accounts of Catholic Christianity. Because Tamil Catholicism functions more as a communal designation than an ideological identity, and overlaps in practice with Tamil Hinduism and Tamil Islam, individuals form a Catholic identity which persists no matter which beliefs or practices they share in common with Hindu or Muslim neighbors or their active participation in others’ worship.