The First Crusade by Thomas Asbridge

How can you love your enemy and kill him? Contrary to our modern assumptions, finds Murrough O'Brien, Crusader knights worried about such a parado

This proclaims itself a "new history", which seems unwise. There is a simpering self-regard implicit in the adjective. "Gracious," the author might be smirking, "I'm not suggesting that this is 'definitive' or anything, just new." But this history is indeed innovative, in that it confounds many of the clichés hovering over the First Crusade, and does so with rigour and charity. At the battle of Dorylaeum, the crusaders kept up their spirits with an inspiring, if ambiguous, battle cry: "Stand fast together, trusting in Christ and the victory of the Holy Cross. Today may we all gain much booty.'' Thomas Asbridge shows us how the billing in this exhortation switched, how the carrot replaced the cross.

It's all too easy, when dealing with the Crusades, to fall back upon the formula: "the motives were mixed.'' But Asbridge rightly will have none of this. He points out that in the 11th century the supposedly barbaric nobles of Western Europe were not, in fact, wondering how they could grab lots of easy loot from decadent easterners; some, like Tancred of Hauteville, were simply trying to resolve a dilemma which rationalists have patronisingly assumed to be one which only modern, enlightened Christians have to contend with: how can you love your enemy and kill him?

So the call of Urban II to deliver the Holy Land from the Saracen came at a time of spiritual crisis, and promised to defuse it. The Byzantine emperor, Alexios Comnenos, wanted hardy Franks to help expel the invading Turks from Asia Minor. But the Pope, not, as now, the unchallenged Pontiff of the Church Militant, needed to unite his fractious sons. So the cry became "Jerusalem''. The emperor, hoping for reinforcements, ended up playing host to a horde. After initial setbacks, and with no uncontested leader, the Crusaders nonetheless succeeded in fighting their way across the Levant, till they clasped blood-stained hands in prayer at the church of the Holy Sepulchre.

So much is well known, but Asbridge has more to tell. The "Peoples' Crusade'', the advance guard of the crusade proper, was not just a wild-eyed mob led by fanatics; its military leaders were as disciplined as any that followed. But without the guidance of the emperor, it had no chance. The later crusaders were more prudent. With judicious and generous use of first-hand accounts, Asbridge presents a disarmingly diverse picture of the crusaders. One moment they are lauded or vilified as mythical monsters, tearing earth and bowels in their unstoppable progress, the next they seem like cheery tourists trading in village bazaars.

So it's a great shame that this comprehensive refutation of scholarly cliché should suffer from literary cliché: metaphors jostle for the honour of being the most hackneyed. The author has a beef with mysterious "modern historians'', who are never named. The evocative quotations from contemporary chroniclers are rarely accredited except in footnotes, which is deeply frustrating.

With the conquest of Jerusalem, it seems that most went home. How ironic the charge that the Crusaders fought only for gain, when you consider how the Land of Milk and Honey turned out to be a desert, the local Christians, whom they had sworn to defend, hostile and heretical. Surely those who stayed did so not for what they had gained but for what they had lost.