So why, we might wonder, do we assume the opposite? Bayly suggests five reasons, the last two of which are quite challenging.

The first is that, as children of the French Revolution, we have unwittingly swallowed the rhetoric of the philosophes: organised religion, and Christianity in particular, were part of the ancien regime, and should by now have been consigned to the dustbin of history by a mixture of popular uprisings, intellectual maturity and political progress. The fact that this did not in fact happen—and that, as Bayly notes, the influence of organised religion grew at precisely the time that Kant, Diderot, Voltaire and co predicted it would disappear—is inconvenient, but like many other simple modern myths (“the glories of Rome,” “the Dark Ages,” “Renaissance,” “Enlightenment,” and so on), it has sticking power.

Secondly, and closely related to the first, is the influence of anticlericalism in the Western intellectual tradition, even where (as in Mill, for example) religion itself was praised for its benefit to the poor. It is not just that the Church in France possessed immense wealth and power; the Church in Europe, and the Roman Catholic Church more specifically, was increasingly identified as the bogeyman from which the bien-pensants were trying to escape—an anticlericalism that was reinforced, not always fairly, by clashes over scientific questions like Copernicanism and Darwinism. The anticlerical sentiment has coloured the Western story ever since.

Thirdly, there is the dominant paradigm of Marxism in leftish intellectual circles right through to the 1970s and 1980s. The Marxist narrative sees no ongoing place for religion once class consciousness has reached a tipping point, so the clear expectation is that religion will gradually fade with the advent of a self-aware proletariat. Again, this did not in fact happen, but because Marxist analysis suggested it should have, many people hardly noticed.

Fourthly, and most challengingly for those of us who are evangelical Christians, Bayly argues that revivalism has played a big part. Revivalism, he explains, requires a narrative of religious decline in much the same way as Marxism and Enlightenment philosophy do, albeit for opposite reasons: when the Church is in decline, and everything is going to pot, it is time for the true Church to rise up, take religion seriously, and keep the flag flying. (And the rockets’ red glare, the bombs bursting in air, gave proof through the night that the Church was still there ...) As such, revivalists have the tendency to exaggerate the bleakness of everyday religion for polemical purposes; it heightens the call for radical obedience, and increases the contrast when revival actually occurs. This then reinforces the narrative of decline, even when the Church is in fact growing worldwide.

Finally, we all suffer from good old-fashioned ethnocentrism, such that the Europeans among us treat the health of the global Church and the health of the European Church as one and the same. If religion is facing stern tests and challenges in Europe, we assume, then it must be on the wane worldwide; if Christendom is thriving, then all is well. This, it barely needs saying, is not the whole picture when it comes to Christianity (let alone to religion in general, which is more the focus of Bayly’s analysis here). Even if the Church in Europe was in retreat from 1789-1914—and, as we have seen already, this was nothing like as true as we think—this would tell us very little about the state of the Church across the world, of which quite the opposite was true.

Theory says that the nineteenth century should have been a century of religious decline. Practice suggests it was a century of expansion, growth, and even triumph. Fancy that.