the First Crusade

The Seljuks and Byzantines continually fought for control of Anatolia and Syria. The Seljuks, who were orthodox Sunni Muslims, formerly ruled a large empire ("Great Seljuk") but by the time of the First Crusade it had divided into many smaller states after the death of Malik Shah I in 1092. Malik Shah was succeeded in the Anatolian Sultanate of Rüm by Kilij Arslan I, and in Syria by his brother Tutush I, who died in 1095. Tutush's sons Radwan and Duqaq inherited Aleppo and Damascus respectively, further dividing Syria amongst emirs antagonistic towards each other, as well as Kerbogha, the atabeg of Mosul.[10]

Egypt and much of Palestine were controlled by the Arab Shi'ite Fatimids, whose empire was significantly smaller since the arrival of the Seljuks. Warfare between the Fatimids and Seljuks caused great disruption for the local Christians and for western pilgrims. The Fatimids, at this time ruled by caliph al-Musta'li, with the vizier al-Afdal Shahanshah holding actual power, had lost Jerusalem to the Seljuks in 1076, but recaptured it from the Ortoqids, a smaller Turkic tribe associated with the Seljuks, in 1098, just before the arrival of the crusaders.[11]

The heart of western Europe itself had been relatively stabilized after the Christianization of the Saxons, Vikings, and Magyars by the end of the tenth century. However, the breakdown of the Carolingian Empire gave rise to an entire class of warriors who now had little to do but fight among themselves.[12] The random violence of the knightly class, and often knighthood itself, were regularly condemned by the church, and the Peace of God was established to prohibit fighting on certain days of the year. At the same time, the reform-minded Papacy came into conflict with the secular world, resulting in the Investiture Controversy, and popes such as Gregory VII needed theological justification for the subsequent warfare. It became acceptable for the Pope to utilize knights in the name of Christendom, not only against political enemies of the Papacy, but also against Muslim Spain, or, theoretically, against the Seljuks in the east.[13]