The Cluny Museum in Paris has probably the best medieval collection in Europe - illustrated manuscripts, church ornaments and tapestries, including the famous Lady with the Unicorn. By the time of the revolution, there were only five monks left in the great Burgundian monastery of Cluny, but it had once been a European power, centre of a monastic system that stretched from Scotland to Poland. In its great days - the 11th century, the core of Tom Holland's book - it had vast economic weight because the monks were far ahead with agriculture, but for the poor put-upon peasantry, it also meant a point of warmth in a very cold world. As the feudal system began to develop, local lords built their castles and sent out their chain-mailed retainers to exact dues and services, drove the peasants into debt, and turned them into serfs. The monks, whose monastery was itself constructed on castle lines, gave them protection. Well-intentioned people left land and money to the Cluniacs, and they became quite rich. The popes in Rome developed a bureaucratic system, and the church was powerful enough to defy rulers.

This is not an era that is easy for an outsider to understand, and "medieval" is not a compliment in any language. There is a splendid book, Régine Pernoud's Pour en Finir avec le Moyen Age, which explains that to understand the middle ages, you have to appreciate that, for them, faith had the same role as physical health does for us. The points for comparison make an amusing party game, what with jogging as penitence and persecution of those modern heretics, smokers. The first millennium, 1000 AD, provides Holland with a good starting point. Various exaltés, their heads stuffed with the Book of Revelation, predicted the end of the world. They died of disappointment.

Holland mentions the millennium scare of 1000 AD, but moves on: the essential dates are 1054, 1066, 1071 and 1077. The book ends with 1095, when the first crusade was proclaimed and Europe moved into the high middle ages: the age of the great cathedrals, when her supremacy in machinery, weaponry, the management of credit and much else got under way. Religion was central to this, and there is even a plausible theory that it led to the invention of clocks, because monks had so many rituals to perform. It is perfectly right for Holland to claim a great deal for the 11th century, of which his book is a splendid, highly coloured canvas.

The central drama, which opens the book, is the battle between a papacy and a German imperialism that were both developing fast. Canossa (1077) has entered the world's vocabulary: a German emperor, Henry IV, standing in the snow, barefoot and penitent, outside an Apennine rock-fortress, begging a pope for forgiveness. The pope kept him waiting because he did not quite know what to do (which had been Henry's intention). If he forgave, he let down his German allies; if he did not, he abandoned his own Christian doctrine. But at bottom, there was a question of great significance for the future: should church and state be separate? Emperor and pope had been fighting over who had the right to nominate bishops. Often enough, Germans would arrive with an army in Rome and - sometimes with the support, sometimes not, of Roman aristocrats manipulating mobs - would sit their own Leo or Clement on the rickety papal throne. But as the Cluniac system grew in importance, so did popes, with a sense of their own role as heirs of St Peter. Gregory VII was one such, and, as a German himself, he could play Germans. He was also dealing with a Christianity beginning to re-define itself, and in 1057 there was a battle in Milan as to who should be bishop. Milan was home to a version of what we might now call "bazaar Islam". A reformist movement, the Patarenes, attacked priests for marrying: they wanted celibacy, and one possessed Cardinal, Pier Damiani, attacked women as "tidbits of the devil ... stuff of sin". A fight with Henry IV followed as to who had the right to nominate the Milan bishop, and it spread into Germany, which at the time was in a semi-permanent state of civil war. Holland is very good at sorting out this central question of German history, which led towards the thirty years war and the country's failure to develop as a nation state. Back and forth the battle went, with excommunications, enlistments of thug-allies, family treacheries, until Henry IV decided to go to Canossa. In the short term, Gregory won, but he had been deceived: Henry advanced again, and Gregory died in exile. I have a bone to pick with Holland at this point. I do not think that he understands sex. Damiani was one of those fanatics - by nature a hermit, and a vegetarian - who advanced priestly chastity, an absurdity with no biblical backing; and the Patarene heresy was eventually taken up by the Cathars, who refused to eat anything that was the product of the sexual act.

Alain Besançon writes of the Cathars that they had "an intellectual hatred of creation". At the bottom of all this is a view of the world as hopelessly sinful which edges into the great theological question of the day: how far Jesus Christ was a man. The British do not really like questions of this sort, arguing that they are really to do with bureaucratic machinations. That is certainly Holland's view when he talks about the great schism of 1054 that divided the Latin from the Orthodox church: in Constantinople, priests married, a long-term consequence of which may even be that, whereas Latin Christianity is now going the way of the old Nestorians, Orthodoxy flourishes.

Holland is weaker on the Orthodox world than he is elsewhere. He is very good indeed, however, on the spread of the Normans, third-generation Vikings, who, in the mid-11th century, constructed a network from Iceland to the Black Sea, the centrepiece of which was post-Hastings Anglo-Normandy. They nearly took over France, and maybe the central question underlying Holland's book is: if they had succeeded, would France have become England? Many Frenchmen might like the idea, poor souls.

 Norman Stone's World War One: A Short History is published by Penguin.

Interviews with classics professors in newspapers went out of fashion roughly around the same time as liberty bodices and national service. Yet mirabile dictu, what should have been featured some weeks ago in the Review section of The Observer if not an interview with a classics professor? To be sure, Mary Beard has always made for good copy. In her ability to make a complex subject accessible to non-specialists, not to mention her occasional aptitude for controversy, she is the closest that her discipline has to a Richard Dawkins. Even so, she is only primus inter pares

This autumn, a whole legion of books by heavyweight classicists will be advancing on bookshops. In addition to Beard's study of Pompeii, enthusiasts for ancient history can enjoy biographies of Philip II of Macedonia, Julius Caesar and Attila. Most unexpected of all is a dense yet wholly gripping analysis by Robin Lane Fox of the Greek dark ages, a period that even specialists have always regarded as intimidatingly obscure. Something rather startling is evidently going on: publishers seem to believe that classical scholarship may actually sell.

For the practitioners of a discipline that has long been beleaguered by charges of irrelevance and snobbery, this is a heady thought. Even in the Fifties, when a knowledge of Latin and Greek was still held to be the defining mark of the nation's educational elite, the perceived pointlessness of studying dead languages was proving toxic. In How to be Topp, one of Geoffrey Willans and Ronald Searle's tetralogy of satires about life in a Fifties prep school, the gloriously disaffected Molesworth advised that a Latin lesson could always be brought to a grinding halt by the simple expedient of asking: 'What is the use of Latin, sir?' He went on to describe the result. 'Master clutches the board ruber but he knos he is beaten this one always rouses the mob.'

Molesworth was right. Over the past few decades, classicists have suffered a rout on the scale of the Roman defeat at Cannae. A discipline that once enjoyed an Olympian status in the curriculum has been struggling for survival. In the state system, where the carnage has been particularly severe, a bare 15 per cent of secondary schools offer Latin. No surprise, then, that it has ended up more thoroughly the preserve of the privately educated than it was even in Molesworth's time. Hardly the perfect background, you might think, for a sudden explosion of interest in the ancient world.

And yet that is exactly what it has provided. The virtual eradication of classical subjects from the state system has left whole swaths of the population educationally disenfranchised: cut off from a knowledge of civilisations that remain no less the bedrock of our own, no less peopled with remarkable figures and famous names, no less fascinating, terrifying and strange than they had ever been. People are not stupid - they know when they are missing out on something interesting and important. If the education system fails to give it to them, then it can hardly be held surprising that they will look for it elsewhere, in works of popular history, perhaps, and in other media as well.

It is surely no coincidence that Gladiator, the film that effectively served to fuel the recent obsession with the ancient world, should have been released in 2000, a generation after the final collapse of classical studies in most schools. Maximus's heroics gave people a taste of what had been lost. Nor did it take long for Gladiator to reveal a quality not normally associated with sword-and-sandal fests: prescience. Watch it again now and it seems to display something of the quality of the best science fiction, a portrait of a world that is as weirdly familiar as it is strange, as much about the future as the past. Citizens fed on dazzling entertainments; armies striking at an elusive foreign foe; the hi-tech delivery of weapons of fire. Here, as with Blade Runner, was a mirror being held up to the future.

One year on from Gladiator's release and the American response to 9/11 ensured that the comparison of the classical superpower to the modern was transformed into a cliche. The image of George Bush wearing an imperial laurel wreath became a staple of caricatures everywhere. The rise and fall of the Roman empire began to seem not just ancient history, but a theme of pressing immediacy. Even now, with American hegemony looking more frayed than it did at the time of the Iraq War, the world of the classical past continues to cast an eerie shadow. As the critical response to the current exhibition on Hadrian at the British Museum has served to suggest, we find it hard now to look at a Roman and not identify in him something of ourselves.

There is nothing new about this. In the Renaissance, when classics as an educational discipline had its birth, Machiavelli had no doubts as to the abiding relevance of the lessons of the Greek and Roman past. 'Prudent men are wont to say,' he wrote, 'and this not rashly or without good ground, that he who would foresee what has to be should reflect on what has been, for everything that happens in the world at any time has a genuine resemblance to what happened in ancient times.' Such a claim, prior to the fall of the Berlin Wall, might have appeared outlandish, but now, with the Cold War ended and long-suppressed identities and hatreds emerging from the melting permafrost, it appears a good deal less so.

Whether in the Balkans or Georgia, not to mention in the former Roman province of Judaea, the origins of modern conflicts often have very ancient roots indeed. Even in Britain, where the increasingly diverse nature of our society has prompted endless tortured musings on the nature of 'British values', the political and moral ambiguities of classical history suddenly seem possessed of a wholly new relevance. Issues of citizenship, after all - for good and bad - lay at the very heart of the Greek and Roman experience. As in the Renaissance, so now: classical scholarship is coming to seem bizarrely cutting edge.

All of which serves to raise a tantalising possibility: that the very devastation to which the discipline has been subjected might end up providing the necessary context for its revival. Perhaps, like any outmoded brand, classics needed to go through a decontamination process. Certainly, it seems now to have purged itself of many of its more rebarbative associations: the fust of chalkdust, the hint of canes and cold showers.

Molesworth, describing the desperate flannelling of a classics teacher put on the spot, imagined him protesting: 'Er latin gives you not only the history of Rome but er [hapy inspiration] its culture, it er tells you about interesting men like J Caesar, hannibal, livy, Romulus remus and er lars porsena of clusium.' To Molesworth's classmates, such names would have been a reminder of ink-spattered textbooks and lectures on the vital importance of a stiff upper lip; children today are likeliest to have heard of them from computer games or glossy TV dramas.

And if that does inspire some students to contemplate the study of a dead language at school, then at least they will no longer find the educational establishment standing in their way. As Will Griffiths, the director of the Cambridge School Classics Project, puts it: 'When we talk to schools about the possibility of offering Latin, we encounter interest and excitement, not hostility.'

Perhaps, then, just perhaps, the rash of books on classical subjects currently appearing in the review pages is indeed the reflection of a broader trend. Certainly, the discipline does appear to have stopped flat-lining. In 2000, there were a mere 150 non-selective state schools in England offering Latin; now there are more than 500.

All of which may be so much whistling in the wind. Enthusiasts for classics, like supporters of the England football team, are forever hailing new dawns and invariably end up disappointed. Nevertheless, like a phalanx of scarred and combat-hardened hoplites, classicists remain, at the very least, on the field of battle. Later this year, for instance, an £8m appeal, 'Classics for All', will be launched, with the stated ambition of making classics 'available and sustainable in all state schools'. What prospect there is of raising such a sum in the teeth of a recession remains to be seen, but the organisers of the appeal are no more likely to be daunted by that reflection than the Athenians were by the sight of the enemy on the plain of Marathon. 'Ignis aurum probat': 'It is fire that truly puts gold to the test'.

Five to read: new classical titles

Pompeii: The Life of a Roman Town by Mary Beard (Profile)
Whirlwind tour of the lost town, punctuated with cheerful myth-busting by the provocative Beard.

Travelling Heroes by Robin Lane Fox (Allen Lane)
Engaging guide to the lives of the Greeks in 800BC, the age of Homer.

Philip II of Macedonia by Ian Worthington (Yale)
Biography of formidable military commander, better known as Alexander the Great's father.

Attila the Hun by Christopher Kelly (Bodley Head)
Keenly argued account of the rapacious warlord's assault on the Roman Empire.

Julius Caesar by Philip Freeman (JR Books)
Caesar's life was lived on epic scale, as this detailed biography reveals.