Thomas Cromwell has lately been enjoying a renaissance. Prior to 2009, if people had heard of him at all, they most likely thought of the brutish and cynical fixer in Robert Bolt’s play A Man for All Seasons (memorably portrayed by Leo McKern in the 1966 film version). Or they might have remembered something from A-level history about an important, if rather grey figure in Tudor governmental reform and the dissolution of the monasteries. Hilary Mantel’s luminescent novel Wolf Hall, its 2012 sequel Bring Up the Bodies and the subsequent stage and screen adaptations have changed all that. Cromwell is now a household word, at least in middle-class households. Dinner table deployment of the name is more likely to evoke Thomas than Oliver, as the Civil War continues its slide down the scale of English historical consciousness and the Tudors maintain their seemingly unshakeable dominance.

Diarmaid MacCulloch’s hugely impressive new biography, meticulous and magisterial, thus meets a reading public with arms open to receive it. An initial thought, which MacCulloch himself articulates, is how remarkable it is that no really heavyweight scholarly biography has previously appeared. Anyone with insider knowledge of Tudor historiography knows who ought to have written one: Sir Geoffrey Elton (1921–94), the Cambridge Regius Professor of History who devoted a lifetime to studying the workings of Tudor government and Cromwell’s role in it in particular. Elton, a German-Jewish refugee coming to Britain in the 1930s, likely empathised with Cromwell as a fellow outsider scaling the heights of the Establishment. But as a historian of rigidly constitutionalist outlook, Elton did not really approve of biography as a genre. His professed interest was in Cromwell as the architect of a ‘Tudor revolution in government’, in which personalised ‘medieval’ rule was replaced with the embryonic institutions of a modern bureaucratic state.

MacCulloch, Elton’s one-time doctoral student, dedicates the book to his former mentor, but wisely spends little time jousting with Elton’s Cromwell. The ‘Tudor revolution’ thesis has in any case been thoroughly debunked by other independent-minded former students of Elton, such as David Starkey, who have demonstrated that the Tudor court was not simply a venue for royal flirtation and frivolity but the crucial political institution of the age. In an era of personal monarchy, when direct access to the sovereign was everything, how could it have been otherwise? Elton’s Cromwell was a fundamentally ‘secular’ figure, more concerned with governance than godliness, but Susan Brigden (another former student) argued some years ago that Cromwell was a convinced and consistent patron of Protestant reformers, a thread running likewise through MacCulloch’s account.

Indeed, Mantel seems to exercise greater intellectual influence over this biography than Elton. (MacCulloch has planted his flag some months before the likely publication of The Mirror and the Light, the final volume in Mantel’s Cromwell trilogy.) A leitmotif of Mantel’s novels is that Cromwell always remained in some sense Cardinal Wolsey’s man, loyal to the memory of the disgraced royal minister who had once been his gracious master – and, crucially, determined to visit revenge on the cardinal’s erstwhile enemies. MacCulloch explores this idea more thoroughly and seriously than any previous historian. This is not, I think, an instance of cashing in, but a rare and interesting example of how an exercise of historical imagination can act as a spur to serious scholarly investigation. It has not previously been noted, I think, just how much Cromwell’s unique role as Henry VIII’s ‘vicegerent’ for ecclesiastical affairs derived from Wolsey’s former position as papal legate.

This insight also helps MacCulloch make sense of an episode that has consistently puzzled historians: the fall and execution of Anne Boleyn in 1536, a sensational denouement that Cromwell himself, in conversation with the imperial ambassador, claimed to have achieved. Assuming, as most historians do, that Boleyn was not in fact guilty of incest and adultery, the likeliest explanation for her fall is that Cromwell engineered it. One of Boleyn’s biographers, the late Eric Ives, expertly showed how she and Cromwell had fallen out over the direction of foreign policy and over what should happen with the proceeds of monasteries then starting to be dissolved. Nonetheless, it seems an extreme, risk-laden solution to a temporary political crisis, as well as a spectacular own goal for the religious reform movement, which, in the teeth of Henry VIII’s often conservative instincts, Cromwell and Boleyn were jointly committed to furthering.

While conceding Cromwell and Boleyn to be common adherents of a loosely defined evangelicalism, MacCulloch finds little evidence of any prior co-operation in the cause of ‘the gospel’. Disagreements about alliances – Boleyn favoured a French one, Cromwell an imperial – were of long standing. And (as Mantel underlines) Boleyn was an inveterate hater of Wolsey and had done more than anyone to erode Henry’s confidence in him. Cromwell most likely received a nod from the king in 1536, but had his own reasons for bringing the queen down.

Debts to fiction only extend so far, of course. MacCulloch has done an extraordinary job scouring the archives for clues about Cromwell’s early life, convinced his later career can only be understood in light of it. His father, Walter, may or may not have been the violent bully portrayed in Wolf Hall, but he was a prosperous Putney yeoman and brewer, hovering just the wrong side of ‘gentle’ status. MacCulloch finds a local loyalty to Surrey and personal connections from childhood persisting throughout Cromwell’s life. Belatedly ennobled for service to Henry VIII, he took the title Baron Cromwell of Wimbledon – a kind of trolling of the high-and-mighty old aristocracy. At the same time, Cromwell was ‘an exceptionally cosmopolitan Englishman’. He served as a soldier in the Italian wars at the turn of the 16th century; one of many intriguing and original insights in the book is that Cromwell’s Italian expertise – linguistic, commercial, political – was a consistent key to his advancement. Englishmen with Italian connections, on both sides of the growing religious divide, pop up surprisingly frequently throughout the book.

In the conduct of public affairs in the 1530s, Cromwell seems ubiquitous and MacCulloch does more than any previous scholar (or even previous scholarship in aggregate) to track the range of his activities. There is a fascinating retelling of a familiar story: his role in dissolving monasteries. Cromwell was not, MacCulloch argues, ideologically wedded to complete appropriation of monastic assets; the Court of Augmentations – set up to handle the windfall, and the centrepiece of Elton’s ‘Tudor revolution’ – turns out not to have been his idea. Cromwell was, however, deeply concerned with the regulation of weirs and waterworks, a subject of possibly greater concern to some of the gentry. We learn of Cromwell’s adeptness in managing the governance of Wales, his much less sure hand (with future consequences) in attempting the same for Ireland and an apparent lack of interest in the affairs of Scotland. Another blind spot was the north of England, where Cromwell lacked connections and clientage: he was the target of vicious antipathy during the 1536–7 Pilgrimage of Grace.

MacCulloch’s Cromwell is an undeniably attractive individual, whose ‘catholicity of friendship’ facilitated good relations with religiously conservative figures (including Princess Mary), even as the Reformation divide widened. His moral centre (reform of religion aside) was love for his only and somewhat wilful son, Gregory. While Cromwell’s greatest political triumph was securing an official English Bible, his greatest personal triumph was Gregory’s marriage in 1537 to a sister of Jane Seymour, making Cromwell, in a sense, the king’s uncle. ‘Cromwell was preoccupied with the future of his dynasty at least as much as the King was with his,’ MacCulloch writes. Despite his spectacular fall in the wake of the Anne of Cleves debacle, Cromwell’s descendants were respected members of the English aristocracy into the later 17th century.

The dark side is Cromwell’s role in the violence meted out to the king’s enemies, most prominent among them Thomas More. Setting Cromwell against More is, of course, a very Mantelian game and, to his credit, MacCulloch for the most part doesn’t play it. There is frank recognition, for example, that Cromwell directed torture to be used against suspected traitors. It is also reasonable for MacCulloch to point out that Henry was the driving force behind the murderous coercion. Yet Cromwell was centrally involved and just about the best MacCulloch can say is that he doesn’t seem to have deliberately starved to death the Carthusian monks imprisoned in Newgate in 1537. More’s ‘relish’ for burning heretics, his ‘savage’ and ‘bitter’ polemics, are implicitly contrasted with Cromwell’s pained performance of unpleasant duties. A tendency to regard killing people for treason as less morally reprehensible than killing them for heresy is, we might reflect, itself the cultural legacy of Tudor propaganda.

Still, it is healthy and appropriate for biographers to empathise with their subjects and to make the most plausible case on their behalf. MacCulloch’s achievement in creating such a vibrant and rounded portrait is all the more remarkable in light of an evidential anomaly noted at the outset. We possess vast numbers of letters addressed to Cromwell, but very few written by him: ‘the man’s own voice is largely missing’. Historians are used to dealing with gaps in the archival record, but MacCulloch makes them a central and absorbing part of his story, speculating that copies of Cromwell’s outgoing mail were systematically destroyed by his household staff at the time of his arrest, and identifying moments when exchanges with particular correspondents, or on particular topics, seem suspiciously thin. He requires us to think about what we don’t know and why we might not know it.

At just over 550 pages of text, and with much detailed delineation of property arrangements, kinship networks and patronage connections, this is a book that will make demands on the general reader, and perhaps deter the casual one. The stout-hearted will be rewarded, however, not least by the dry wit and warm humanity peppering MacCulloch’s work. If this is not the definitive biography, I don’t know what that would look like.