This essay explores the eclectic spirituality of the late-nineteenth-writer Marie Corelli, with specific reference to her fiction. I look to her first novel, A Romance of Two Worlds (1886), as a case study with which to explore the relationship between Christian orthodoxy and heterodoxy in a secular age. In doing so, I draw on recent theoretical contributions to our understanding of the sacred and the secular in the late nineteenth century, and I question the tendency of many critics to presume that Corelli’s interest in spirituality has little or nothing to do with Christianity. Corelli wrote that her “creed has its foundation in Christ alone,” and although there are good reasons for investigating that claim more closely, these investigations do not have to result in a secular reading and/or an interpretation that breaks from Christianity. By situating Corelli’s fiction within the Christian tradition, I show how she helps us rethink the way in which we draw and redraw the boundaries of religious belief at the fin de siècle.