A detailed study of one of the most exciting episodes of the Middle Ages - the Crusades. The author, an eminent British scholar, provides a wide-ranging overview of the history of Byzantium and Islam, and the religious disputes that led to the emergence of many Christian churches. The book examines the history of the origin of the very idea of the crusader movement, its hidden reasons. The main stages of the First Crusade are given. The relationship between its participants, their enemies and allies is shown. The story continues until the newly formed Kingdom of Jerusalem receives its first king.