The Byzantine Empire survived in the East with its capital at Constantinople until 1453. The emperors were absolute rulers chosen in theory by God and were responsible for preserving the traditions of Roman justice.

Byzantium was the buffer that cushioned Europe against frequent invasions from the north and east. The Byzantine armies and navies were well organized and led. The Byzantines also developed great diplomatic skill.

In philosophy, the Muslims eagerly studied Plato, Aristotle, and the Neoplatonists. Like the Byzantines and the western Europeans, they used what they learned to enable them to solve theological problems.

The reign of Mamun the Great (r. 813-833) is often said to mark the high point in the development of Arabic science and letters. In Baghdad he built an observatory, founded a university, and ordered the great works of Greek and Indian scientists and philosophers translated into Arabic.

The Arabs brought their new religion and their language to the peoples they conquered. The religion often stimulated new artistic and literary development, and by requiring a pilgrimage to Mecca, it fostered mobility among the Muslims and encouraged the exchange of ideas with fellow Muslims from other parts of the Muslim world. Since Arabic had to be learned by everyone who wished to read the Koran, it became the standard written language of the whole Islamic world.

The Arabs had overrun a vast collection of diverse peoples with diverse customs. Moreover, internal dissensions among the Arabs themselves prevented the establishment of a permanent unified state to govern the whole of the conquered territory. After Muhammad’s death, there was disagreement over the succession. Finally, Muhammad’s eldest companion, Abu Bekr, was chosen khalifa (caliph, the representative of Muhammad). Abu Bekr died in 634, and the next two caliphs, Omar (r. 634-644) and Othman (r. 644-656), were also chosen from outside Muhammad’s family.

Scholars used to believe that the startling expansion of Islam was due to the zeal of converts to the new faith. Now students of early Islam often argue that overpopulation of the Arabian peninsula set off the expansion. The first stages of the advance into lands already infiltrated by Arabs. The movement quickly gathered momentum; Islam was its battle cry, but its motives included the age- old ones of conquest for living space and booty.

What we know of Muhammad is derived from Muslim authors who lived sometime after his death. The Arabia into which he was born about A.D. 570 was inhabited largely by nomadic tribes, each under its own chief. These nomads lived on the meat and milk of their animals and on dates from palm trees. They raided each other’s flocks of camels and sheep and often feuded among themselves.

Islam (the Arabic word means “submission to God”) is the most recent of the world’s great religions. Its adherents (Muslims, “those who submit” to God) today inhabit the entire North African coast, much of central and west Africa, part of Yugoslavia, and Albania, Egypt, Turkey, the entire Near and Middle East, Pakistan, parts of India, the Malay peninsula, Indonesia, and the Philippine Islands, as well as central Asia and portions of China. Relations with the Muslim world have been crucial to Western civilization since Muhammad founded Islam in the early seventh century.

The Church of Hagia Sophia (Holy Wisdom) in Constantinople, built in the sixth century, was designed to be “a church the like of which has never been seen since Adam nor ever will be.” The dome, says a contemporary, “seems rather to hang by a golden chain from heaven than to be supported by solid masonry.”

Byzantine achievement was varied, distinguished, and of major importance to the West. Byzantine literature may suffer by comparison with the classics, but the appropriate society with which to compare medieval Byzantium is the Europe of the Middle Ages. Both were Christian and both the direct heirs of Rome and Greece. The Byzantines maintained learning on a level much more advanced than did the West, which, indeed, owes a substantial cultural debt to Byzantium.

Scholars have disputed whether agriculture or commerce was economically more important in Kievan Russia; the answer appears to be commerce. In trade, with Byzantium in particular, the Russians sold mostly furs, honey, and wax—products not of agriculture but of hunting and beekeeping. Since the Byzantines paid in cash, Kiev had much more of a money economy than did western Europe. From the economic and social point of view, Kievan Russia in the eleventh century was in some ways more advanced than manorial western Europe.

Beginning in the eighth century, the Scandinavians expanded into Russia. First taking control of the Baltic shore, they moved south along the rivers to the Sea of Azov and the northern Caucasus. Their name was Rus, which has survived in the modern term Russian. Gradually they overcame many of the Slavic, Lithuanian, Finnish, and Magyar peoples who were then living on the steppe. The story told in the Old Russian Primary Chronicle, compiled during the eleventh century, is suggestive of what may have happened among the inhabitants of Russia sometime in the 850s:

The first Slavic people to fall under Byzantine influence were the Bulgarians. From the time these barbarians crossed the Danube in the late seventh century, they engaged in intermittent warfare against the Byzantine Empire. At the same time, a Slavic people called the Moravians had established a state of their own. Their rulers associated Christianity with their powerful neighbors, the Germans, and feared both German and papal encroachment.

Perhaps the major Byzantine cultural achievement was the transmission of their civilization to the Slays. Much as Rome Christianized large groups of “barbarians” in western Europe, so Constantinople, the new Rome, Christianized in eastern Europe.

Although intrigue and the violent overthrow of sovereigns remained a feature of Byzantine politics, the people developed a deep loyalty to the new ruling house that was established in 867 by the Armenian Basil I (r. 867-886) and called the Macedonian dynasty because of his birth there. As political disintegration began to weaken the opposing Muslim world, the Byzantines counterattacked in the tenth century. They captured Crete in 961 and Antioch and much of northern Syria in 962.

In 717-718 Leo III, who had come to the throne as a successful general, defeated the Arabs who were besieging Constantinople. Thereafter the Byzantine struggle against the Muslims gradually became stabilized along a fixed frontier in Asia Minor.

The emperors immediately following Constantine were Arians until Theodosius I (r. 379-395), who in 381 proclaimed orthodox Nicene Athanasian Christianity to be the sole permitted state religion. All those who did not accept the Nicene Creed were to be driven from the cities of the Empire. The Empire, East and West, was united under Theodosius, but his sons Arcadius (r. 395-408) and Honorius (r. 395-423) divided it, with Arcadius ruling at Constantinople.

Despite their efforts, the emperors at Constantinople could not reconquer the West and thus reconstitute the Roman Empire of Augustus. Indeed, theological controversy, reflecting internal political strain, and combined with Persian and Arab aggression, cost the Empire Syria and Egypt. The internal structure was modified to meet the new situation.

A difference in the wording of the liturgy, it is sometimes argued, caused the schism, or split between the Eastern and Western churches in 1054. The Greek creed states that the Holy Ghost “proceeds” from the Father; the Latin adds the word filoque, meaning “and from the son.” But this and other differences might never have led to a schism had it not been for increasing divergences between the two civilizations.

Yet much of this was also true in the medieval West. The real contrast is most apparent when we compare the relationship between church and state in the West with that in the East. In the West, the departure of the emperors from Rome permitted local bishops to create a papal monarchy and challenge kings and emperors. In Constantinople, however, the emperor remained in residence, and no papacy developed.

Religion governed Byzantine life from birth to death. The church governed marriage and family relations and filled leisure time. Religion also dominated the arts and literature, economics and politics, and intellectual life.

Byzantium was a great center of trade, to which vessels came from every quarter of the compass. From the countries around the Black Sea came furs and hides, grain, salt, wine, and slaves from the Caucasus. From India, Ceylon, Syria, and Arabia came spices, precious stones, and silk; from Africa, slaves and ivory; from the West, especially Italy, came merchants eager to buy the goods sold in Constantinople, including the products of the imperial industries.

The Byzantines, however, preferred negotiating to fighting, and they brought diplomacy to a high level. The subtlety of the instructions given their envoys has made “Byzantine” a lasting word for complexity and intrigue. First Persia and then to some extent the Muslim caliphate were the only states whose rulers the Byzantine emperors regarded as equals. All others were “barbarians.”

In their endless effort to protect their frontiers the

As defenders of the faith against hostile invaders, the Byzantine emperors fought one war after another for eleven hundred years. Sometimes the invaders were moving north and west from Asia: Persians in the seventh century; Arabs from the seventh century on; and Turks beginning in the eleventh century. Byzantium thus absorbed the heaviest shock of Eastern invasions and cushioned the West against them.

As the direct agent of God, the emperor was responsible for preserving the tradition of Roman law. Only the emperor could modify the laws already in effect or proclaim new ones. Thus he had on hand an immensely powerful instrument for preserving and enhancing power.

After Constantine, Byzantium called itself New Rome. Its emperors ruled in direct succession from Augustus. Yet many non-Roman elements became increasingly important in Byzantine society. A Roman of the time of Augustus would have been ill at ease in Byzantium. After Constantine had become a Christian, the emperor was no longer a god; but his power remained sacred.

At the far southeastern corner of Europe, on a little tongue of land still defended by a long line of massive walls and towers, there stands a splendid city, Istanbul. After 330, when the first Christian Roman emperor Constantine the Great made it his capital, it was often called Constantinople, but it also retained its ancient name Byzantium. For more than eleven hundred years thereafter it remained the capital of the Eastern Roman Empire.