What a remarkable effect Ridley Scott's new film Kingdom of Heaven is having on the discourse of popular culture. Arcane movie website forums, normally devoted to whether a starlet has shaved under her arms that month, are plunging into discussions of medieval history. The movements of 12th century armies are being traced by glossy magazines; the symptoms of advanced leprosy freely discussed in an age that regards the common cold as an insufferable assault.
Most importantly of all, of course, there is being expressed the startling possibility that some historical figures in Christian, western society might have behaved with a murderous impunity towards the followers of a different faith; and that those infidel followers in turn reacted with a gracious forbearance when they had the opportunity to fight back.
To summarise: the unequivocal hero of Kingdom of Heaven is the Kurdish sultan of Egypt and Syria, Saladin, played with finely honed authority by the Syrian actor Ghassan Massoud, while its villains are the rabid Knights Templar of the early crusades. Even the Christian knight who tries to transcend the savagery, Balian of Ibelin, is depicted by Orlando Bloom, an actor of such effete looks and diffident manner that the director is surely trying to weave yet another sly subtext into his subversive morality tale.
Scott's simplified account of self-righteous Christian blood-lust is unjustly exaggerated, say critics. But the spirit of the film is soundly sourced, even if it plays fast and loose with some of the facts. The crusades were seen as just wars against infamous unbelievers for centuries. In the court of Louis XIV, the Jesuit Louis Maimbourg described with gusto how the Christians, once in possession of Jerusalem, "used to their full extent the rights of victory... Everywhere one could see nothing but heads flying, legs hacked off, arms cut down, bodies in slices... they killed the very children in their mothers' arms to exterminate, if possible, that accursed race."
It wasn't until the Enlightenment that a degree of revisionism over the crusades began to be detected in a new generation of philosophers, who were more interested in truth than in religious propaganda. "The more incomprehensible it seemed to those cool, rational spirits, the more they felt the necessity of comprehending it," wrote the historian Hugh Trevor-Roper. For Gibbon, the four holy wars that cost so many lives were "the World's Debate", which is a more wholesome way of looking at it than Samuel Huntington's infamous Clash of Civilizations.
The image of the noble Muslim leader teaching the west a thing or two about tolerance was also born in this period: witness the extraordinary display of clemency by Pasha Selim in Mozart's Seraglio, when he discovers that he is to lose the woman he loves to the son of the man who has dishonoured him. Voltaire shared Scott's admiration for Saladin, and also paid tribute to the Emperor Frederick II, who negotiated with - instead of fighting - the sultan, and was the victim of a papal crusade as a result.
So it is only right that we, like the intellectuals of the 18th century, should debate the legacy of the crusades. Only, we do it through our own cultural channels, none more powerful than Hollywood. Great works of popular culture do not have to be brilliantly written, bursting with originality, or argued with any great subtlety. It is enough that they hit the right nerve, in the right place, at the right time; and then, that they are debated by millions.
Oliver Stone's Wall Street was no great critique of capitalism, yet its caricature soundbites - "Greed is good", "Lunch is for wimps" - were brilliantly evocative of their era. It is impossible to remember the Reagan years without bringing to mind Michael Douglas in his broad red braces. That is what you call real iconic power.
Kingdom of Heaven, too, is touching nerves. It is Osama bin Laden's version of history, thundered a British academic, which will only fuel Islamic fundamentalism. But Scott is following a fine tradition, one established by the bold free thinkers of 200-odd years ago, who reached some unpalatable conclusions when they took their cool, rational look at the results of invoking religion in warfare. The crusades' only gift to Europe, said the inestimable Voltaire, was leprosy.
I am liberal enough to believe that benign depictions of tolerance in art will lead us all to think in a more gracious and tolerant way about alleged enemies. I am also enough of an agnostic to find alarming a US president who lets slip the word "crusade" when addressing a 21st century audience; a British prime minister who prays to God and keeps telling us he took a difficult decision because it was the "right" thing to do; and a new Pope who really seems to believe he is infallible, and that the Enlightenment was some kind of ghastly wrong turn in human history.
And the crusaders? Their most notable "success" was when they turned on their fellow Christians, the Greeks of Constantinople. Otherwise, nothing; or, to quote Gibbon, "a mournful and solitary silence... along the coast which had so long resounded with the World's Debate."
