This dissertation argues that the concept of the 'heathen' expressed the exclusionary and expansionist precepts of English Protestantism in the Atlantic world between c. 1558 and c. 1700. Building upon recent scholarly developments in the cultural history of unbelief and the global history of Protestantism, the dissertation investigates language as a fundamental bridge between theology and culture in England and North America during the Long Reformation. It demonstrates that Protestants deployed the idea of the 'heathen' in historical, polemical, devotional, and colonial contexts in order to reinforce and reconfigure the relationship between the predestinarian framework of salvation, the postlapsarian condition of human beings, and the boundaries of the true church. Imbued with interconnected theological, rhetorical and literal meanings, the figure of the 'heathen' provided Protestant writers with a diachronic non-Christian persona that played a fundamental role in charting the continuously unfolding sacred history of the 'true religion'. The multivalent and adaptable, yet coherent and provocative concept of the 'heathen' reveals that ideas about numerous forms of non- Christianity were essential to the development of Protestantism.

Etymologically derived from the uncultivated environment of the 'heath', the concept of the 'heathen' was pervasive in the English Bibles, where it referred to a fundamental connection between non-belief, idolatry, and the natural world, while also inviting the possibility of salvation through the intertwined physical and spiritual processes of planting, propagation, cultivation and conversion. As a feature of Protestant historical writing about early Christianity in the ancient world, the 'heathen' could refer either to the opponents and persecutors of Christian believers or to prospective converts. Invoking the concept of the 'heathen' could articulate animosity towards Catholicism, but it also exposed the waywardness that seemed to lurk within the professing community of the Church and the individual Christian conscience. Moreover, it could describe the seemingly ignorant and unreformed peoples of rural and remote regions in Britain. The idea of the 'heathen' communicated Protestant efforts to simultaneously exclude such sources of corruption from the Church of England and expand the 'true religion' through the propagation of the Gospel and the conversion of non-Christian peoples. In colonial Virginia and New England, the 'heathen' not only expressed hostility and uncertainty towards the indigenous inhabitants of North America, but also suggested that some non-Christian peoples could be converted and might be saved in accordance with predestinarian and postlapsarian doctrine.

Investigating the relationship between theology and culture through the conceptual lens of the 'heathen' reveals an ambivalent and precarious, yet assertive and enduring Protestant effort to propagate the Gospel among the indigenous non-Christian inhabitants of the Atlantic world. As well as exposing the global dimensions of the Protestant preoccupation with non-belief, the 'heathen' also testifies to the underlying role of religious language in both shaping and challenging perceived connections between Christianity, civilisation, and modernity.