The first wavelet justified Eudemus's generalization that "the invention of the sciences originated in practical needs," and that knowledge for its own sake was not the determining factor. The year had been determined, stone circles erected almost everywhere, and fires signaled from them, giving notice of the longest and shortest days, so that agriculture was provided for, even away from churches and the festivals of the Church. The original user of geometry was not required away from the valleys of the Nile, Tigris, and Euphrates, and therefore it is now medicine and surgery that come to the front for the alleviation of human ills. In the eleventh century we find Salerno, soon to be famed throughout Europe as the great medical school, forming itself into the first university. And medicine did not exhaust all the science taught, for Adelard listened there to a lecture on "the nature of things," the cause of magnetic attraction being one of the "things" in question. This teaching at Salerno preceded by many years the study of the law at Bologna and of theology at Paris. The full flood came from the disturbance of the Arab wave center by the crusades, about the beginning of the twelfth century. After the Pope had declared the "Holy War," William of Malmesbury tells us "the most distant islands and savage countries were inspired with this ardent passion. The Welshman left his hunting, the Scotchman his fellowship with vermin, the Dane his drinking party, the Norwegian his raw fish." Report has it that in 1096 no less than six millions were in motion along many roads to Palestine. This, no doubt, is an exaggeration, but it reflects the excitement of the time, and prepares us for what happened when the crusaders returned. As Green puts it:[37] "The western nations, including our own, 'were quickened with a new life and throbbing with a new energy.' ... A new fervor of study sprang up in the West from its contact with the more cultured East. Travelers like Adelard, of Bath, brought back the first rudiments of physical and mathematical science from the schools of Cordova or Bagdad.... The long mental inactivity of feudal Europe broke up like ice before a summer's sun. Wandering teachers, such as Lanfranc or Anselm, crossed sea and land to spread the new power of knowledge. The same spirit of restlessness, of inquiry, of impatience with the older traditions of mankind, either local or intellectual, that drove half Christendom to the tomb of its Lord, crowded the roads with thousands of young scholars hurrying to the chosen seats where teachers were gathered together."