Rory Rapple is an associate professor in the Department of History at the University of Notre Dame.

Historical figures fluctuate in value. Thomas Cromwell, King Henry VIII’s factotum, is currently at a premium. This, however, has more to do with the reading public’s taste for historical fiction rather than its appetite for actual history books. Hilary Mantel’s Man Booker Prize-winning “Wolf Hall” novels have been a publishing phenomenon, even spawning a television series. But who was the real Cromwell? Diarmaid MacCulloch’s biography “Thomas Cromwell: A Revolutionary Life” will satisfy popular curiosity about Mantel’s protagonist. It’s a gripping story about power, political turmoil and seismic cultural change played out against the backdrop of rule by a psychopath. MacCulloch, the author of many books including “Christianity: The First Three Thousand Years,” not only exhibits a witty and readable writing style, but he also proves himself to be a formidable master of the archive.

From the early 1530s, Cromwell was Henry’s chief enforcer. More than anyone else, he ensured that the king’s misgivings about his marriage to Katherine of Aragon and his passion for Anne Boleyn had lasting consequences. Within a decade, under Cromwell’s political and legal management, England broke from the jurisdiction of the papacy, Henry was proclaimed supreme head of the Church of England, and, after the dissolution of the monasteries, Cromwell presided over the largest transfer of wealth in the history of that country since the Norman conquest of the 12th century. A third of the land in England, formerly belonging to the monasteries, became the king’s property, and much of this was redistributed among England’s aristocracy and gentry. If you have ever wondered why fictional English nobility live in places that go by ecclesiastical names such as Downton Abbey, Cromwell is a large part of the answer.

The sheer accessibility of this book belies the work that must have gone into researching and writing it. Professor G.R. Elton, the doyen of modern Tudor history, famously said Cromwell was not biographable, and with good reason. The minister’s archive, although voluminous, is particularly tricky. Relatively few of his own letters survived; a posthumous purge conducted by well-meaning friends followed his fall from grace and subsequent execution in 1540. As a result, Cromwell is something of a blank canvas — a blessing for a writer of historical fiction but more challenging for a historian.

MacCulloch’s subtitle, “A Revolutionary Life,” is a hat tip to Elton, who doggedly argued that Cromwell was the architect of a constitutional revolution in England. This revolution, it was implied, secured the preeminence of secular constitutional principles and practice throughout the Anglophone world. After Cromwell, England became a place where lay power trumped religious authority, and Parliament ultimately arrogated the job of determining the official doctrine and liturgy of the kingdom. Elton gloried in the way Cromwell’s career combined supreme prowess as an administrator with an unsqueamish ruthlessness in the practice of politics. Consequently, the ultimate decline and fall of such a consummate operator was a puzzler. His cynical Machiavellian qualities had somehow failed him, probably because he had, in the end, become a committed adherent of reformed religion — “he came to believe in it after all,” Elton was once heard to remark, with more than a trace of disappointment.

MacCulloch argues, however, that Cromwell’s religious commitments and enthusiasms were long-standing. This fueled a consistent desire to do what he could to push the process of religious reform in England ever further in an evangelical Protestant direction — a risky business given Henry’s attachment to Catholic orthodoxy in doctrinal matters. Even after his break from the pope, Henry, on the one hand, burned Protestants at the stake for heresy while, on the other hand, he condemned monks to be hanged, drawn and quartered for refusing to renounce papal supremacy. Yet MacCulloch’s Cromwell is far from the archetypal buttoned-down English Protestant. Instead he cuts a gregarious figure. He did not seek the dissolution of the monasteries in order to make a monastery of the world. In fact, according to MacCulloch, his Protestantism was modeled on the contemporary Italian dissenting style: urbane, cultured, worldly, given to clandestine adherence to the faith rather than grandstanding piety. This type of wry evangelicalism was about as close to later English Puritanism as Italian eurocommunism would be to the clunking fist of Stalinism.

But the vexed question of Cromwell’s lethal actions can never quite be avoided. During Henry’s reign, high politics in England was a blood sport, and it’s clear that Cromwell thrived in this deadly environment and reveled in his triumphs, even when they proved fatal to others. He facilitated the destruction of the king’s opponents — a motley crew comprised of conscientious objectors like Sir Thomas More, Bishop John Fisher and the Carthusian martyrs of the London Charterhouse, as well as other unfortunates like the Marquess of Exeter, the Countess of Salisbury and, arguably, Cromwell’s most dangerous enemy, Anne Boleyn herself — who either became collateral damage or were vindictively put down. MacCulloch, however, highlights Cromwell’s tendency to give good counsel to those who opposed Henry’s policies, urging them to see sense, save themselves and shun martyrdom. But this alleged humaneness while pursuing his quarry makes him appear calculating, rather like Lewis Carroll’s virtue-signalling walrus who feigns sympathy with the oysters he shoves in his mouth. In fact, Cromwell was not immune to the occasional thrill of schadenfreude when he destroyed former enemies of his erstwhile patron Cardinal Thomas Wolsey as well as particularly vocal objectors to Henry’s hostile takeover of the church in England, people whom MacCulloch terms “traditionalists.”

As with Mantel’s books, it’s easy to get the impression that MacCulloch wants his readers to like Cromwell. We are to feel some affinity with him, in spite of the fact that he sometimes manipulated the king to crush certain people who threatened him and occasionally trumped up charges against other people whom Henry wanted liquidated.

For all this unpleasantness, Cromwell never seems to have been guilty of the twin sins against modern liberal etiquette of being either priggish or a traditionalist. Indeed MacCulloch’s recurrent use of the term “traditionalist” to describe Cromwell’s contemporaries who retained a conscientious loyalty to the mainstream of Western Christendom occasionally seems somewhat tendentious.

To many contemporary readers, the term “traditionalist” is liable to conjure up the image of marginal unattractive figures, an assumption that would not do justice to those Englishmen and women of all classes who were happy to maintain the religious status quo and valued it over personal gain and even, in some cases, personal survival. By contrast, MacCulloch’s Cromwell emerges as something of a wily progressive, an ideological elitist, a member of the prophetic shock minority. Perhaps we’re meant to think of him as on the side of the angels — the forces of progress — while feeling relief that he isn’t morally threatening. Not for him the implicit moral superiority of martyrdom. Good old Cromwell, he doesn’t make you feel bad.

Thomas Cromwell

A Revolutionary Life

By Diarmaid MacCulloch

Viking. 728 pp. $40