This dissertation argues that nineteenth-century literature anticipated the vibrant interdisciplinary debates that now center on the meanings of secularism. For decades, modernity has been associated with the decline of religion, ignoring the many ways that modern institutions adapted religious feelings and practices, rather than simply discarding them. Indeed, many religious and irreligious nineteenth-century thinkers—including Charlotte Brontë, Matthew Arnold, John Ruskin, and John Stuart Mill—actively grappled with issues of faith and rationality in a rapidly-changing economic, political, and cultural landscape. Prefiguring many of the key insights of the so-called “postsecular turn,” the work of these Victorian writers offers an ideal archive through which to show the various ways in which religion and modernity have been mutually constitutive. Ruskin’s series of essays in Unto This Last uses revamped Christian parable to underline the complicit individualism of Victorian Protestantism—resulting in a “postsecular” critique that anticipates William Connolly’s analysis of neoliberal capitalism. Turning to one of Ruskin’s principal targets, J. S. Mill, allows me to argue that Mill’s reputation as a wholly atheistic utilitarian derives from an impoverished secular understanding of Victorian modernity. Brontë’s Villette uses Gothic conventions to dramatize the challenges of sectarian religious difference through the trans-channel courtship between the Gallic Paul Emanuel and the ultra-Protestant Lucy Snowe. Finally, Arnold’s poetry and essays demonstrate the reemergence of diverse religious and philosophical inputs through a process of modern accretion—not linear subtraction. The nineteenth century offers a prime vantage from which to explore the very issues of religion, modernity, and the public sphere. Turning to the period in light of these concerns allows us not only to better understand the function and purpose of many Victorian literary texts, but also to configure our own engagement with the same questions.