The term “Byzantine Empire” is given to the late Roman Empire from about the 7th century onwards.
At the heart of the Byzantine Empire was the great city of Constantinople. This had been founded by the Roman emperor Constantine (reigned 324-37), as a new capital for the Roman Empire. Its official name was New Rome (Constantinople was its informal name and means “City of Constantine”). Like Rome, its poorer inhabitants received free grain, shipped in from Egypt, and this helped its population grow to about half a million. This made it one of the biggest cities in the world at that time.
The city became the capital of the Eastern Roman Empire. This roughly covered the provinces of Syria, Palestine, Egypt, Asia Minor, Greece and the Balkans. Here, Greek was the international language of commerce and culture, and increasingly of administration as well. Because Constantine was the first Christian emperor, his city, Constantinople, was from the start a major centre of Christianity.
The Eastern Roman Empire continued intact after the Western Roman Empire (comprising Italy, Gaul, Britain, Span and North Africa) fell to German invaders in the fifth century. It was only marginally affected by the invasions of the time, and indeed flourished during the 5th and 6th centuries. Under the emperor Justinian it was able to recover some territory lost in Italy, North Africa and Spain.
In the 7th century, however, the Late Roman Empire suffered huge losses of territory. A massive war with the Persian Empire for a time lost it its most valuable provinces, Egypt and Syria. Under the emperor Heraclius the empire was able to defeat the Persians, but almost immediately a new threat emerged from the east. This was the Arab armies which came sweeping out of Arabia in the name of their new religion, Islam. The Romans now permanently lost Syria, Palestine and Egypt.
Meanwhile, dealing with the threats from the east had drained their military resources in the west, and the Romans lost most of their lands in Europe as well as Avar and Slav invaders moved down from central Europe. The Romans were left with some pockets around the capital, Constantinople, and in Greece.
It is from this time that we should start referring to the Later Roman Empire as the Byzantine Empire. This is a term coined by modern scholars, referring to the old name for Constantinople (Byzantium), and denotes the profound changes that had occurred, or were now taking place, within the empire.
Firstly, Greek had now definitively replaced Latin as the language of government.
The decline of Latin had an important effect on religion and culture. Byzantine clergymen now usually did not know Latin, and most western Clergy no longer understood Greek. This mean that the two groups talked less and less to each other, and Christianity was beginning to diverge into distinct branches. Whereas their essential beliefs would never contradict one another, a host of different practices and outlooks accumulated to drive the two apart. While Western Christianity was evolving into the Catholic Church, Byzantine Christianity was beginning to evolve into the Greek Orthodox Church.
One of the main differences between the two Christian branches was that, whereas in the West the Church stood apart from secular power, in the Byzantine world the Church was very much subordinate to the emperor. Byzantine emperors continued to control the church in a way that was no longer true for kings and princes in western Europe. One consequence of this was that disagreements in religion became political issues; for example, in the 8th and 9th centuries, the Byzantine state was torn from time to time by the issue of whether or not to revere religious icons.
One of the most defining features of Byzantine civilization as opposed to the old Roman civilization was that it was shot through with Christian belief. However, this did not prevent the Byzantine intelligentsia, made up mostly of monks, clergy and officials, of making a concerted effort to preserve the Classical civilization of the Romand and Greeks. We have them to thanks for much of our knowledge of Greek literature and culture.
Nevertheless, Byzantine society was utterly different from Classical society. The provinces which had not been overrun by Arabs from Arabia and the Slavs from central Europe, had become war zones, with enemy forces penetrating deep into Byzantine territory, on several occasions to the walls of Constantinople itself. In these circumstances the thriving city life which had been the basis of Greek and Roman culture disappeared. Towns had become villages. Only a handful of cities survived, by far the biggest being Constantinople itself – though even its population, now deprived of grain from Egypt, was now only a fraction of what it had been in the 6th century.
All these changes in society and culture, plus the need for defence in depth, led to a revolution in government, with the empire becoming divided into military-administrative districts built around the need for self-defence. A class of independent farmer-soldiers grew up, on whom the burden of Byzantine taxes and military service rested.
In the 9th and 10th centuries, a succession of vigorous Byzantine emperors consolidated their control over their existing provinces and expanded their borders on all sides. They defeated the new Bulgar threat to occupy much of the Balkans, and they pushed out their territories in eastern Asia Minor, even occupying some of Syria.
In the 11th century, however, the tide turned against the Byzantines again. They lost their territory in Italy, and then suffered a disastrous defeat at the hands of the Seljuq Turks at the battle of Manzikert (1071). As a result, they lost a large part of Asia Minor, which had been their main recruiting ground for the army, and represented a blow from which they never really recovered.
The Byzantines called on the western co-religionists for military aid, and this launched the famous Crusades by western Christendom to capture Jerusalem from the Muslims. This was by no means an unqualified boon for the Byzantines, and frictions between them and the westerners led eventually to the capture of Constantinople itself by the 4th Crusade (1204).
Western princes divided the Byzantine Empire amongst themselves, although Byzantine regimes-in-exile were soon set up in Greece and Asia Minor. One of these was finally able to retake Constantinople on 1261, and re-found the Byzantine empire.
This was now a mere shadow of its former self, and from the late 13th century the rising power of the Ottoman Turks began to engulf it. Finally, in 1453, the Ottomans captured Constantinople, effectively putting an end to the Byzantine Empire.