'Today the crusades are seen by many Muslims as evidence of unceasing Western aggression against their faith. But for centuries they saw them in a rather different light.
"You often hear people say there has been an abiding resentment amongst Muslims of the crusades," says Professor Jonathan Riley-Smith of Cambridge University. "Nothing could be further from the truth. They thought they had won."
Muslims believed they had emerged victorious because once the Christian fighters stopped coming from the West, the Muslims were left in control of Jerusalem for several centuries.
The revival of the idea of crusaderism as representing an innate Western desire to gain control of the Muslim lands only re-emerged during the colonial period. But since that time it has had great resonance. Today Osama bin Laden uses the term to motivate young Muslims to attack Western targets.
"It has become crystal clear that the West in general, led by America, harbours a crusader hatred against Islam which is beyond words" he said shortly after 9/11.'