The Caliphate at Baghdad was already a power past its peak. Its authority had once stretched all the way from the Pyrenees to the frontiers of China, but Moslem Spain had been ruled by a separate Caliphate since the mid-8th century, and Egypt and much of North Africa was subject to the Fatimids, a Shiite dynasty. Then in the 11th century the Seljuk Turks, emerging from Central Asia, first occupied Iraq and seized control of the Caliphate, and then in 1071 defeated the Byzantines at Manzikert and flooded into Anatolia, not only turning it permanently into Moslem territory, but transforming the farms of the Greek cities which had dotted the region since the days of Alexander the Great into pasture for sheep. The Seljuk Sultanate did not remain united for long, but the entire balance of the Neat East had been destroyed for ever.
Further west, Moslem power was in retreat. In Spain, Toledo fell to Christian forces in 1085, and for the next four hundred years Moslem Spain continued to shrink, until finally extirpated at Granada in 1492. There was another permanent change in Italy, where a family of Norman warlords, the Hautevilles, descendents of an obscure knight called Tancred, conquered Sicily and set up their own state there, fighting Moslems and Byzantines indiscriminately.
So weak and threatened was the Byzantine Empire after Manzikert that the Emperor Alexius was driven to ask for help from the knights of the west, whom he knew well as opponents and mercenaries. The result was the First Crusade, which was not at all what Alexius had envisaged, but which forced its way through the Turks in Anatolia to take Jerusalem from the Egyptians in 1099 and thereafter raided as far as Egypt and the holy city of Mecca.
Western Europe at the time was a region of weak central authority. The Kings of France had little control over the great lords, and much of present-day France was controlled by the Kings of England; a position which did not change until the early 13th century, when Philip Augustus drove King John of England out of almost all his French possessions. The most powerful state was the Holy Roman Empire, established by Otto the Great in the 10th century, covering Germany and northern Italy. Otto and his successors forcibly intervened in Rome to end a succession of scandalous Popes, opening the way to the pontificate of the great reformer Gregory VII (1073-85). But the claims of the new papacy to universal authority led to conflict with the Emperors which was to tear Italy apart for the next century and a half. The new emerging Italian city-states were able to play off the two rival claimants against each other, as “Guelfs” (supporters of the Pope) or “Ghibellines” (supporters of the Emperor); and as a result, Italy never developed as a nation-state. Almost unnoticed amidst this conflict, a breach came about between the Roman and Byzantine churches in 1054, which became permanent.
The Kings of the western European countries played no part in the First Crusade, which was purely a matter of private enterprise and religious enthusiasm (in varying combination) by great feudal lords, pilgrims and Italian merchants. The reconquest of Spain was similar, with the famous El Cid (Rodrigo Diaz de Vivar: 1043-99) very much an individual freebooter rather than an obedient follower of any King. (Monarchs led the Second and Third Crusades, but without any great degree of success)
The motive that drove the Christian knights and lords was the hunger for land, which they would then hope to rule with as little control from above as possible. This hunger drove the Normans to conquer England in 1066, and to continue thence into Ireland and the Scottish lowlands; whilst at the same time other Normans were overrunning southern Italy and Sicily, and ultimately invading Palestine. (When judging the extreme cruelty of the Normans to anyone who got in their way, we must remember that really they were only second-generation Vikings, with a thin veneer of Christianity which had very little effect on their behaviour)
The feudal states that resulted from this hunger were decentralized, with a strong tendency to fall into anarchic disorder. It is not surprising that between the crusading knights and the city-dwelling, bureaucratically-governed Byzantines there quickly grew up a profound mutual suspicion and mistrust. The early crusaders actually felt more empathy with the Turks, whose approach to life was not too different from their own. The mutual respect between Richard the Lionheart and Saladin should be seen in the same light: Saladin came from a family of Kurdish mercenary warriors, and he and Richard could understand each other more than either of them could understand a Byzantine emperor. Saladin’s reputation in the west was such that, within a century, Dante accorded him a place amongst the “Virtuous pagans”, whilst many Christian monarchs and even some Popes were depicted writhing in the nether reaches of hell.
Saladin’s recovery of Jerusalem from the crusaders was matched in importance by his takeover of Egypt, where he restored the Sunni faith. Western mistrust of the Byzantines culminated in the disgraceful episode of the Fourth Crusade in 1204, when the crusaders sacked Constantinople itself. Once again, no state was involved, unless we count the Republic of Venice, which cynically manipulated the campaign for its own benefit.
So by the early 13th century, the whole picture of the Near East was different. The eastern Mediterranean was now dominated by Christian ships, especially those of Venice and Genoa. Moslem power had been permanently expelled from Sicily, and was in irreversible retreat in Spain. The Byzantine Empire was shattered, and would be unable to resist a later resurgence of Turkish attacks. Saladin had reunified the main centres of the Islamic world, but the Caliphate was now an empty shell, and the Middle East was about to suffer the hammer-blows of the Mongol onslaught. In the west, stronger states were starting to emerge, but the general picture was still one of feudal anarchy. Except in the Slav regions of eastern Europe, the supply of new land for settlement was drying up. Kings and nobles were less interested in crusading than in rivalry with each other. The Papacy was an independent power in its own right, with claims to universal sovereignty. The world had changed.