It used to be an open secret that most historians of Christianity had axes to grind - partisans fighting their confessional corners, ecumenists trying to spread peace and love, non-believers out to debunk, ex-believers out for revenge. But it was still a secret, in the sense that most scholars tried to preserve a veneer of Rankean objectivity. What made The Stripping of the Altars (1992) such an earth-shaking book was its full-throated, visceral religiosity.
Here is a book dedicated to God himself - in the words of the Latin Mass for the dead, no less. For the heart of Eamon Duffy's achievement was to turn his own religious commitment into a scholarly strength, not the embarrassing peccadillo that such commitment had long been assumed to be.
As an interpretation of English Reformation history, there was nothing particularly revolutionary about The Stripping of the Altars. The argument, essentially, was that pre-Reformation English Catholicism was a vibrant, popular, unified and flourishing tradition; a tradition that was then wantonly, deliberately and violently destroyed by a small clique of Protestant extremists. Others had made similar arguments, and while this picture can be overstated, precious few scholars today reject it entirely.
Duffy's particular achievement, though, was to show us "traditional religion" (not "popular" religion, he insists: the elite shared it, too) at parish level. And Duffy, an Irish Catholic born in 1947, understands this tradition in his bones. He can explain how, for example, an illiterate people could fully understand a Latin liturgy even if they could not actually translate it. He rescues medieval Catholicism from both the caricatures of later Protestantism and the condescension of later Catholicism.
In the process, Duffy attacks the traditional boundary between medieval and early modern studies, with its submerged implication that at some point in the early 16th century, everyone decided to put on tights and to become forward-thinking Tudor rationalists. The Reformation was not a battle between medieval and modern, but between a universal tradition and a gang of barbarians.
Wildly partisan? Of course. And there are certainly problems. His contrast between a timeless, pious merry England and the narrative of assault and violence is queasily like the distinction between Eden and the Fall. He also downplays any signs of dissidence or deviance in "traditional religion".
But he has changed the discipline, for three reasons. First, the sheer mass of evidence his scholarship has accumulated. This is a fat book, which, as a review quoted on the cover insists, is "not a page too long". Second, it makes sense of so much else. Scholars with Protestant sympathies frequently agree with Duffy about much of what happened, if not with his tone of lament. His rehabilitation of Mary I - long remembered as "Bloody Mary" - has been particularly compelling.
Lastly, the passion with which he writes gives the reader not merely a shrewd historical argument but a compelling vision of what it meant actually to live this traditional religion. It is a vision that a secular historian could not have given us.