Byzantine missionaries, led by two brothers, Cyril and Methodius, converted the Slavs of eastern Europe to Christianity. They adapted the Greek alphabet to the Slavic tongues and taught the people to read and write. To this day, the Russians and many of the Balkan Slavs use the modified Greek or Cyrillic alphabet. Byzantine influence has also been very important in their religion, government, and art. Western Europe was also greatly indebted to the Byzantines. The desire for Byzantine products stimulated the revival of commerce. Through the Byzantines, Europe also rediscovered much of the culture of ancient Greece and Rome. And for centuries, while the peoples of the West were slowly constructing their new civilization, Constantinople served as a bulwark for Christianity
The Crusades or Holy Wars began largely as a result of events in the East. At the beginning of the 11th century, a nomadic people from central Asia, the Seljuk Turks, invaded Mesopotamia and gained control of the caliphate of Bagdad. Later they expanded westward, defeated the. Byzantines, and conquered all of Asia Minor. The Byzantine emperor sent frantic appeals to the Pope for help. His pleas were echoed by pilgrims, who returned form the Holy Land with tragic tales of mistreatment. Because the Seljuk Turks had recently embraced a new religion, Islam, they were intolerant, as new converts are inclined to be. Scholars, however, believe that the stories of Seljuk atrocities were greatly exaggerated. Religious zeal and idealism were probably the main inspiration of the Crusaders. They were anxious to safeguard their fellow Christians in Constantinople and to regain control of the Holy Sepulcher from the Seljuks. Moreover, the Pope had granted remission of their sins and entry into Paradise if they perished while fighting the “infidels” As far as the Byzantines were concerned all the Crusades accomplished was to reduce the power and influence of the Byzantine armies. In the Fourth Crusade, Venetian merchants and shipowners diverted the Crusaders into attacking Veniceâ€™s great trade rival, Constantinople. Despite the protests of the Pope, the Crusaders conquered the city, establishing a Latin Empire in the East. The Byzantines recovered control about a half-century later, but their
empire never regained its former strength. Moreover, after such a betrayal, there was little hope that the westerners and the Byzantines would co-operate against the Moslems.
Byzantium played a large part in the building up of the civilization of Islam. The Arabs that came out of the desert were simple people. Very few of them were literate. As they swept across the Near East and through Anatolia into Byzantium controlled areas, they picked up and borrowed almost all the refinements that they subsequently acquired from the peoples they conquered. They borrowed from the Persian but much more from the Hellenistic Semitic Christian civilization of Syria and Egypt. This civilization, already Byzantine, even after the conquest, was continually being aided by Byzantium. The removal of the Moslem capital to Bagdad increased the Persian influence on Islam, even though Baghdad was built partly by Greek architects and masons.
The Byzantines had been taking severe setbacks from the encroaching Seljuk, then later Ottoman, Turks. Byzantine power had been on the decline for years; the government was almost bankrupt and could not afford to maintain its necessarily large armies. It is as the seers of Byzantium foretold, the prophets that spoke incessantly of the fate that was coming, of the final days of the city. The weary Byzantine knew that the doom so often threatened must some day surely envelop him.