During this period of excitement and terror the number of pilgrimages to the Holy Land had enormously increased, so much so that the Saracen masters of Jerusalem, with the view of putting a stop to the now troublesome and inconvenient influx of Christians to the Holy City, commenced to persecute the pilgrims, thus creating a very great ill-feeling against themselves throughout Europe. Peter the Hermit, a monk of Amiens, took up the cause of his ill-treated brethren, and forthwith commenced to preach a holy war against the Saracens of Syria, Pope Urban II. and his priests promising absolution from all sin to those who took up arms against the Infidel. A vast multitude of rabble from all parts of Europe soon started on their march to the Holy Land, being divided into three large armies, one led by Walter the Penniless, another by Peter the Hermit, and the third by Gottschalk, a monk. The armies gave themselves up to unheard-of iniquities, spreading poverty and misery on all sides in their march, braining all who refused to give up their provisions and property to them, and, at last, arriving in Constantinople footsore and diseased, having left two-thirds of their comrades to die of starvation on the road. Crossing over into Syria, they met the Saracen foe, who quickly put an end to their sufferings by annihilating the whole lot. Seven other Crusades followed, one composed altogether of children, who, the priests declared, were to be the inheritors of the Holy Land, it being now apparent that full-grown men were too sinful to conquer the Infidel. The army of children was accordingly shipped off to destroy the Saracen foe, but never reached Palestine, the boys having been sold as slaves, and the girls drafted into Turkish harems. When, at last, Acre surrendered to the Crusaders under Richard Cœur de Lion, the leniency displayed by the Khalif Omar in his capture of Jerusalem in 637 was repaid by 2,700 Saracen hostages being brutally beheaded outside the city walls for the sport of the Christian soldiers. All this time Europe was in a constant state of agitation and alarm, which was further intensified by the revival in 1180 of the doctrines of John Erigena by the Saracen philosopher Averroes, who boldly preached them in Spain, making converts in all directions, among whom was the great Jewish writer, Maimonides, who had been held by the Jews in the highest esteem, and considered second only in wisdom to Moses.