In the 12th century, Peter the Venerable, Abbot of Cluny, initiated a dialogue with the Islamic world. "I approach you not with arms, but with words," he wrote to the Muslims whom he imagined reading his book, "not with force, but with reason, not with hatred, but with love." Yet his treatise was entitled Summary of the Whole Heresy of the Diabolical Sect of the Saracens and segued repeatedly into spluttering intransigence. Words failed Peter when he contemplated the "bestial cruelty" of Islam, which, he claimed, had established itself by the sword. Was Muhammad a true prophet? "I shall be worse than a donkey if I agree," he expostulated, "worse than cattle if I assent!"

Peter was writing at the time of the Crusades. Even when Christians were trying to be fair, their entrenched loathing of Islam made it impossible for them to approach it objectively. For Peter, Islam was so self-evidently evil that it did not seem to occur to him that the Muslims he approached with such "love" might be offended by his remarks. This medieval cast of mind is still alive and well.

Last week, Pope Benedict XVI quoted, without qualification and with apparent approval, the words of the 14th-century Byzantine emperor Manuel II: "Show me just what Muhammad brought that was new, and there you will find things only evil and inhuman, such as his command to spread by the sword the faith he preached." The Vatican seemed bemused by the Muslim outrage occasioned by the Pope's words, claiming that the Holy Father had simply intended "to cultivate an attitude of respect and dialogue toward the other religions and cultures, and obviously also towards Islam".

But the Pope's good intentions seem far from obvious. Hatred of Islam is so ubiquitous and so deeply rooted in western culture that it brings together people who are usually at daggers drawn. Neither the Danish cartoonists, who published the offensive caricatures of the Prophet Muhammad last February, nor the Christian fundamentalists who have called him a paedophile and a terrorist, would ordinarily make common cause with the Pope; yet on the subject of Islam they are in full agreement.

Our Islamophobia dates back to the time of the Crusades, and is entwined with our chronic anti-semitism. Some of the first Crusaders began their journey to the Holy Land by massacring the Jewish communities along the Rhine valley; the Crusaders ended their campaign in 1099 by slaughtering some 30,000 Muslims and Jews in Jerusalem. It is always difficult to forgive people we know we have wronged. Thenceforth Jews and Muslims became the shadow-self of Christendom, the mirror image of everything that we hoped we were not - or feared that we were.

The fearful fantasies created by Europeans at this time endured for centuries and reveal a buried anxiety about Christian identity and behaviour. When the popes called for a Crusade to the Holy Land, Christians often persecuted the local Jewish communities: why march 3,000 miles to Palestine to liberate the tomb of Christ, and leave unscathed the people who had - or so the Crusaders mistakenly assumed - actually killed Jesus. Jews were believed to kill little children and mix their blood with the leavened bread of Passover: this "blood libel" regularly inspired pogroms in Europe, and the image of the Jew as the child slayer laid bare an almost Oedipal terror of the parent faith.

Jesus had told his followers to love their enemies, not to exterminate them. It was when the Christians of Europe were fighting brutal holy wars against Muslims in the Middle East that Islam first became known in the west as the religion of the sword. At this time, when the popes were trying to impose celibacy on the reluctant clergy, Muhammad was portrayed by the scholar monks of Europe as a lecher, and Islam condemned - with ill-concealed envy - as a faith that encouraged Muslims to indulge their basest sexual instincts. At a time when European social order was deeply hierarchical, despite the egalitarian message of the gospel, Islam was condemned for giving too much respect to women and other menials.

In a state of unhealthy denial, Christians were projecting subterranean disquiet about their activities on to the victims of the Crusades, creating fantastic enemies in their own image and likeness. This habit has persisted. The Muslims who have objected so vociferously to the Pope's denigration of Islam have accused him of "hypocrisy", pointing out that the Catholic church is ill-placed to condemn violent jihad when it has itself been guilty of unholy violence in crusades, persecutions and inquisitions and, under Pope Pius XII, tacitly condoned the Nazi Holocaust.

Pope Benedict delivered his controversial speech in Germany the day after the fifth anniversary of September 11. It is difficult to believe that his reference to an inherently violent strain in Islam was entirely accidental. He has, most unfortunately, withdrawn from the interfaith initiatives inaugurated by his predecessor, John Paul II, at a time when they are more desperately needed than ever. Coming on the heels of the Danish cartoon crisis, his remarks were extremely dangerous. They will convince more Muslims that the west is incurably Islamophobic and engaged in a new crusade.

We simply cannot afford this type of bigotry. The trouble is that too many people in the western world unconsciously share this prejudice, convinced that Islam and the Qur'an are addicted to violence. The 9/11 terrorists, who in fact violated essential Islamic principles, have confirmed this deep-rooted western perception and are seen as typical Muslims instead of the deviants they really were.

With disturbing regularity, this medieval conviction surfaces every time there is trouble in the Middle East. Yet until the 20th century, Islam was a far more tolerant and peaceful faith than Christianity. The Qur'an strictly forbids any coercion in religion and regards all rightly guided religion as coming from God; and despite the western belief to the contrary, Muslims did not impose their faith by the sword.

The early conquests in Persia and Byzantium after the Prophet's death were inspired by political rather than religious aspirations. Until the middle of the eighth century, Jews and Christians in the Muslim empire were actively discouraged from conversion to Islam, as, according to Qur'anic teaching, they had received authentic revelations of their own. The extremism and intolerance that have surfaced in the Muslim world in our own day are a response to intractable political problems - oil, Palestine, the occupation of Muslim lands, the prevelance of authoritarian regimes in the Middle East, and the west's perceived "double standards" - and not to an ingrained religious imperative.

But the old myth of Islam as a chronically violent faith persists, and surfaces at the most inappropriate moments. As one of the received ideas of the west, it seems well-nigh impossible to eradicate. Indeed, we may even be strengthening it by falling back into our old habits of projection. As we see the violence - in Iraq, Palestine, Lebanon - for which we bear a measure of responsibility, there is a temptation, perhaps, to blame it all on "Islam". But if we are feeding our prejudice in this way, we do so at our peril.

Karen Armstrong is the author of Islam: A Short History

Source: Guardian