"Eleventh-century chroniclers drastically revised early medieval history to demonize Muslims. A famous example is the beautiful eleventh-century poem Le Chanson de Roland, which depicts a 778 engagement in the Pyrenees between Charlemagne and the evil Saracens, describing an ambush by the deceitful Muslims in which the Christians valiantly defended themselves. Like Muslims, the Christians, too, could write poetic war propaganda. In truth, Charlemagne had already made a deal with competing Muslim leaders and easily took Spanish cities by a prearranged collaboration. But then, having not fought any real battles, on his way back to France he sacked Pamplona, a Basque city. It was the Basques and not the Muslims who attacked his rear column in the mountain pass. In reality there were not two all-powerful forces, the Christians and the Muslims, but many warring groups. Urban II unified the Christians by creating this myth of a single, all-powerful Saracen, which for a time was a great Christian advantage since there was no unity among Muslims."