The way in which recent conferences about religion and politics have been framed reveals hidden assumptions: ‘Religion Confronts the Secular State’, ‘Is Religion Compatible with Liberal Democracy?’, ‘Post-Secular Conditions: Challenges to Citizenship, Law, and Democracy’. Such titles lend support to a widespread view that secular states are the norm, and that they are being challenged by a recent ‘resurgence’ of (illiberal) religion, a development which threatens to shift religion from the private to the public sphere, and in doing so raises urgent new questions about whether liberal-democratic states and societies can or should accommodate the unexpected intruder. This chapter questions every one of these assumptions: that religion was ever separate from the modern state, politics and public life; that religion and liberalism are inevitably at odds with each other; and that secularism has a more constitutive relation with liberalism than religion. For the sake of brevity, examples are taken from the British situation, but the argument applies more widely.

Let me begin by sketching what I mean by liberalism. First, I mean something wider than ‘liberalism’ as it appears in those political theory textbooks where it is presented as a political ideology alongside conservatism, socialism, Marxism and so on. This is a bloodless abstraction of liberalism: detached from history, institutional embodiment, compelling symbolic forms and social life.

The previous chapter explored the way in which dreams of universal dominion helped shape the fortunes of early Christianity and support the rise to power of the Catholic church. Such dreams lost nothing of their allure as antiquity gave way to the Middle Ages. Men of power still imagined themselves at the helm of great empires, and they were men of religion as well as of politics – for as yet there were no secular empires, only religious ones.

Yet the Christian empire was threatened by competing powers, both religious and political. The words above are those not of a Christian but of Mani (216–76), the founder of a new universal religion that, he believed, would supplant those that had come before, including Christianity. Mani's dream faltered because his religion failed to form an adequate alliance with political power. The next great world empire, the Islamic, did not make the same mistake. Its dramatic rise to power from the seventh century, and its rapid seizure of territories belonging to the Roman empire, would have serious consequences for the development of Christianity.

It is generally accepted that Pope Stephen II (752–7) set the western church on a novel course when he appealed to King Pippin III of the Franks to restore conquered papal lands, and bestowed on him the title Patricius Romanorum. In so doing, Stephen was turning his back on the eastern empire in favour of what he hoped would become a new empire with its centre in Rome. This move was justified, to later generations at least, by The Donation of Constantine, quoted above, a forgery from the eighth century, whose authenticity was queried only in the fifteenth. Purportedly written by the emperor Constantine on the eve of his move to Constantinople, it bestowed power in the west to the pope of the time and to his successors.

Bunyan's Pilgrim's Progress, published in England in 1678, became a Protestant classic. It offered an allegorical tale of one man's struggle to overcome sin and win salvation, and succeeded in translating the objective truths of Protestant theology into the subjective experience of ‘Pilgrim’, the Protestant everyman.

Those who have followed this book from start to finish will notice that the story has come full circle. It began with a religion that was marginal to social power, and it ends with a religion that has become marginal to social power once more. The fact that Christianity lost influence over the spheres of political, economic, military and even ideological power does not, of course, mean that it necessarily loses influence over individual lives. It does, however, mean that such influence is likely to take particular forms. It will be felt at the personal rather than at the public level, and Christian ethics will be concerned with the regulation of personal, intimate and domestic life. In so far as Christianity continues to have an impact on political and economic life, it will do so by shaping behaviour and commitment at the individual level. Some churches may continue to make pronouncements about war, politics and economics, but they will do so from the margins rather than from the centre, and without any guaranteed influence. Grand theological systems are likely to be eclipsed by teachings that have an immediate relevance to the individual in the living of his or her life. Rather than having an established status in society, Christianity has, once again, to fight for that place with a wide range of competitors.

So wrote Eusebius (c. 260–c. 339), bishop of Caesarea, in celebration of thirty years of imperial rule by the Roman emperor Constantine. Three centuries had passed since the death of Jesus. Eusebius had reason to rejoice. Under Constantine Christianity had changed its status from being a cult within the mighty Roman empire to being an officially tolerated religion. Encouraged by Christians such as Eusebius, Constantine had readily accepted the status of deputy of Christ. With the blessing of the ‘Supreme King’ in the heavens, his ambition to become supreme king on earth was gaining new impetus and legitimacy.

One of the most skilful, powerful and ruthless of the Roman emperors, Constantine had harboured ambitions to unify and expand the Roman empire even before his ‘conversion’ to Christianity in 312. During the course of his long reign – from 306 to 337 – his commitment to Christianity increased until it became the favoured religion of the empire. The reasons appear to have been political as well as personal. Christianity offered something unique in the ancient world: an exclusivist, universalist, monopolistic monotheism focused on a single all-powerful God. Roman religion was generally pluriform and tolerant.

The reformer Martin Luther (1483–1546) promised freedom. He promised freedom from the burden of the moral law; freedom from fear of the devil and damnation; freedom from obedience to the pope and his church. Every infant, he proclaimed, ‘crawls out of the font [at baptism] a Christian, a priest, and a pope’. He himself had been set free by the belief that no-one and nothing stood between him and God. But Luther also embraced the role of a servant in relation to his God. He found freedom in complete, unswerving devotion to the God who had saved him by sending his Son Jesus Christ. As the servant of the most powerful master of all, a master who elevates those he loves, Luther could no longer be enslaved to any earthly power. As he put it in The Freedom of a Christian, he, like his fellow Christians, was not only ‘a perfectly dutiful servant’ but ‘a perfectly free lord, subject to none’.

What Luther had done, in effect, was to slice out the multiple mediating authorities that had stood between the individual and God in medieval Christianity. A Christian had to tread carefully, making sure that the higher powers that controlled his or her destiny were kept sweet.

Though a final verdict will be possible only when the passage of time allows us to take a longer perspective, the final part of the twentieth century may be judged one of the most momentous in the history of Christianity. For in just three decades, between 1970 and 2000, Christianity collapsed in parts of the northern hemisphere, and gained new vitality in much of the south.

It was not just Christianity that changed; the world changed too. Eric Hobsbawm is not alone in noting the historical significance of the changes that took place in the second part of the twentieth century. The widespread sense that something of such magnitude had occurred that it constituted a break with what had gone before was signalled by the use of terms such as ‘postmodern’, ‘post-industrial’, ‘post-Christian’ and ‘post-colonial’. Though these terms are much debated, few disagree that the last part of the twentieth century witnessed an erosion of long-established forms of social order and moral control. Negatively, such collapse involved a dissatisfaction with established, hierarchical orders, and may be characterised as a ‘flight from deference’.

Simply by dissolving the unity of Christianity, the Reformation had a profound effect on the Catholic church. It was not that post-Reformation Christians were left with choice of religious affiliation, for in most cases their faith would still be determined by the society and family into which they were born. But after the Reformation, Europeans were no longer simply born ‘Christian’. However dim and distant the threat of Protestantism might seem to, say, an Italian peasant, he would now be aware that he possessed a ‘Catholic’ identity that set him apart from some other so-called Christians north of the Alps.