With Rubicon and Persian Fire, Tom Holland proved himself a master of narrative history with a sizeable weakness for relating the ancient world to the modern. His third history blockbuster, Millennium, dials back the parallels but finds its narrative coherence threatened.

It’s still a very readable and interesting book – a thorough exploration of a relatively obscure period in European history, covering the time from the coronation of Charlemagne in 800 to the culmination of the First Crusade in 1099. Holland doesn’t dwell on either event, looking instead to less well-known – but more crucial – turning points: the victory of Otto over the Hungarians at the Battle of Lech; the rise to power of the Abbey of Cluny; the humbling of Emperor by Pope at the fortress of Canossa, which Holland contends represents the crucial division of Church and State on which Christendom was founded.

All this was new to me, all of it intriguing and well-told. Holland’s style is evocative, picaresque even: he likes to present his sources with their mentality intact, which means taking at face value stories of visions, dragons, portents and miraculous occasions. He’s sure-footed enough never to labour the doubtfulness of these tales, trusting the reader to pick out when the tellers believed their yarns and acted accordingly and when the convenience of the claims is a little too neat, as with the remarkable discovery by one abbey of the head of John The Baptist, helpfully encased completely within a stone pyramid.

On a broader level, though, Millennium doesn’t quite come together. The hook Holland has picked to hang his tales on is the millennial expectations of the era – the general conviction that “the world has grown old” and the last days of mankind were upon its inhabitants. The problem is that it’s quite hard to pinpoint this millenarianism as a motivating factor for most of the book’s action – certainly some individuals were driven by it, like the young Emperor Otto III, groomed by his religious mentor (and later Pope) to rekindle the Roman flame and bring on the End Times. But for most of Millennium’s cast of conniving nobles, Viking and Norman looters, monks and Patriarchs, the looming end of days is simply part of the mental scenery, and there’s scant evidence it affected the usual human pursuits of jockeying for status and money and worrying about one’s immediate future. Impending doom – as recent nuclear and current environmental crises testify – tends simply to be too big to affect individual behaviour much: saying a few more prayers was the 10th Century equivalent of recycling a few more papers, and probably not much less tangential to the daily grind. Especially as it was often outsourced to monks.

What’s frustrating about Millennium is that there are other, more gripping themes in the book. As the year 1000 passes without the world’s end, and the year 1033 likewise (dedicated Apocalypse watchers simply shifted expectation from the anniversary of birth to that of death), the tempo of the story hardly slackens. The real plot of Millennium is one of history driven by innovation – partly liturgical innovation, the monks at Cluny devising elaborate rituals*(and engineering political change) to turn their Abbey into a kind of continental salvation machine, protecting Europe with a forcefield of prayer and helping create an ideological unity across the region. But mostly technological innovation, particularly the rise of castle-building.

Castle-building in Millennium, and the development of mounted knights that accompanied it, was the innovation that turned medieval society even more radically asymmetric. Flung up with shock-and-awe speed across a conquered landscape, the castle – routinely described now as a defensive innovation – in fact worked as an offensive base, an HQ from which to mount oppressive raids across a territory and wipe out further resistance. The rise of castle walls was a source of extreme dread to local peasantry and the parasitic knight class a scourge which required monastic intercession to deal with. The newly authoritative monks saw the Knights as potential shock troops for Christendom, recognition of which would give said troops the moral authority to turn pillage into permanent settlement. This set in motion what must be one of the biggest bits of spin doctoring in history – the imaginative transformation of mounted thugs on the make into the noble and chivalrous orders of later renown.

This is a great story, and makes Millennium a better book than the slightly tenuous apocalyptic material would allow by itself. It also somewhat justifies the enormous digression on the Norman Conquest, a whole chapter spent on English domestic politics in a book whose more general thrust they have little to do with. Generally, though, I was left with a feeling that the sheer scope of the book – from the settlement of Iceland to the origins of Russia, from the imperial policy of Constantinople to the internal strife of the Caliphate in Spain – left it groping for unity. For instance, the evocative opening at Canossa, presented as a seismic development, later falls into place more as a skirmish – not the first, hardly the last – between Emperor and Pope, and the upper hand gained by the Papacy being far from decisive. This all results in Millennium ending up a fascinating but frustrating read – one that in some ways demands a slightly less neatly packaged sequel.

*someone wanting to write a Holland-esque history book that works as a nudge-wink towards our own times could do worse than look at the development of liturgical instruments, which took a simple principle – intercession against sin, or theological insurance – and gradually made it vastly more complex, until the guaranteeing of pardons against future sins had become a vast industry and a bedrock of the Church’s finances. The Reformation as a derivatives bubble? Could be a goer!