the First Crusade

The origins of the crusades in general, and of the First Crusade in particular, are varied and are widely debated among historians. They are most commonly linked to the political and social history of eleventh-century Europe, the rise of a reform movement within the Papacy, and the political and religious situation of Christianity and Islam in Europe and the Middle East. Christianity, which had spread throughout Europe, Africa, and the Middle East in the early Middle Ages, was by the early eighth century limited to Europe and Asia Minor after the rapid spread of Islam. The Umayyad Caliphate had conquered Syria, Egypt, and North Africa from the predominantly Christian Byzantine Empire, and Spain from the Christian Visigothic Kingdom.[3] In North Africa, the Ummayad empire eventually collapsed and a number of smaller Muslim kingdoms emerged, such as the Aghlabids, who entered Italy in the 9th century, and the Kalbids, who became prey to the Normans capturing Sicily by 1091. Pisa, Genoa, and Aragon began to battle other Muslim kingdoms for control of the Mediterranean, exemplified by the Mahdia campaign and battles at Majorca and Sardinia.[4]

At the western edge of Europe, and of Islamic expansion, the Reconquista in Spain was well underway by the eleventh century; it was intermittently ideological, as evidenced by the Epitome Ovetense written at the behest of Alfonso III of Asturias in 881, but it was not a proto-crusade.[5] Increasingly in the eleventh century foreign knights, mostly from France, visited Spain to assist the Christians in their efforts.[6] Shortly before the First Crusade, Pope Urban II had encouraged Spanish Christians to reconquer Tarragona, near Barcelona, using much of the same symbolism and rhetoric that was later used to preach the crusade.[7]

In the east was the Byzantine Empire, fellow Christians who had long followed a separate Orthodox rite. Since 1054 the Eastern Orthodox and Roman Catholic churches had been in schism, and the imposition of Roman church authority in the east may have been one of the causes of the crusade.[8] Under Emperor Alexius I Comnenus, the empire was largely confined to Europe and the western coast of Anatolia, and faced many enemies: the Normans in the west and the Seljuk Turks in the east. The Seljuks invaded Byzantium in 1071, and in response, in 1074, Pope Gregory VII called for the milites Christi ("soldiers of Christ") to go to their aid. This call, while largely ignored and even opposed, nevertheless focused a great deal of attention on the east.[9]