In 1095, Pope Urban II delivered an electrifying speech that launched the First Crusade. In the largest mobilization since the fall of the Roman Empire, some 100,000 men took up the call, driven on by intense religious devotion, convinced that their struggle would earn them the reward of eternal paradise in Heaven. This book recounts a three-year adventure filled with barbarity: from the mobilization in Europe, where great waves of anti-Semitism resulted in the deaths of thousands of Jews, through the arrival in Constantinople, an opulent city, ten times the size of any city in Europe, that bedazzled the Europeans; to the siege of Nicaea and the pivotal battle for Antioch, where the crusaders routed a larger and better-equipped Muslim army. When a hardened core finally reached Jerusalem in 1099, they brutally slaughtered thousands of Muslims--men, women, and children--in the name of Christianity. The First Crusade marked a watershed in relations between Islam and the West, a conflict that set these two religions on a course toward enduring enmity.