In 1095, Pope Urban II started preaching for an expedition to the Holy Land in reaction to a request by Alexius I Comnenus [the Byzantine emperor], for mercenary soldiers to fight the Seljuk Turks. But the western answer was altogether more ambitious, asking huge numbers of military pilgrims under their own leaders, who crossed Europe and Asia Minor to reach Syria, and arrived Jerusalem in 1099. They initiated a series of outside campaigns (crusades as they were later called) which mobilized the military possible of Christendom. Initially, the crusaders found the new conditions challenging: the heat, difficult terrain, and the fluid tactics of a nomadic enemy. The big siege of Antioch taught them how to overcome the Muslims in battle and worked a veteran force. At Jerusalem, their mastery of siege technology achieved their goal.
Crusading needed a high level of organisation. Forces had to be raised which would retain military effectiveness for a campaign which might last years in competitive territory far from home. Logistical support would be a constant problem. The First Crusade, the frrst expedition of its kind, was a prevail of improvisation. The troops were advanced by several powerful princes: Raymond, count of St Gilles from south of France; from the north, Godfrey of Bouillon, his brothers, the counts of Flanders and Boulogne, also Robert duke of Normandy who mortgaged the duchy to stock his forces; and the Normans of the south of Italy, led by Bohemond of Taranto. He was experienced in warfare against Alexius and his Turkish mercenaries, and a man of unlimited aspiration and litde scruple, like his nephew Tancred. There was no clear command structure among these known princes. Urban did not follow the expedition, but charged as his legate Adhemar, bishop ofLe Puy. Raymond also needed leaders, but the other princes were unWilling to give him priority.
Angus MacKay, Atlas of medieval europe, London 1997, P. 87.
Nicholas Hooper, The Cambridge illustrated atlas of warfare : the Middle Ages, Cambridge University Press 1996, P. 86.