Also called in English the Eastern Roman Empire, the Later RomanEmpire, or from the Latin name of the Greek city of Byzantion, site of the later Constantinople, BYZANTIUM.
1. Origins. The Byzantine Empire was the continuation of the Roman Empire in the East. From the point of view of its rulers, churchmen and writers, its origins lay back in the age of the Caesars, and they continued to see themselves as the Roman Empire until the Turks stormed Constantinople in 1453.
A significant change was made in the running of the Empire in the 280s. The Emperor Diocletian faced two problems. The Roman frontier, always active in the East where it faced whoever ruled in Iran, was coming increasingly under threat along its length between the deltas of the Danube and the Rhine, particularly from Germanic tribes and federations of tribes.
The second problem was internal. The Army not only made Emperors; at times, it unmade them. In the vastness of the Roman Empire it was not always easy for the Emperor to make his influence felt in trouble-spots, so Diocletian decided to appoint a co-Emperor. In 285 he made Maximian Caesar (junior Emperor), raising him to the rank of Augustus the following year. Maximian took responsibility for the West, Diocletian for the East, but Diocletian was recognised as the senior Augustus.
He was not partitioning the Empire, but dividing responsibilities. In 293 he appointed two Caesars, one for each Emperor, each with his own sphere of responsibility, so that it was much easier to secure the presence of the Emperor if it were needed with the Imperial office in a kind of commission. His successors did not follow the details of his arrangements but the basic principle survived. Normally there were two co-Emperors, responsible for West and East, but one of them was the senior Augustus and so had an oversight over the Empire as a whole.
One Emperor who did not maintain the co-Emperorship was Constantine, though he made close relatives Caesars.. During the last half of his reign, from 324 to 337, he reigned alone, solving the problem of the vastness of the Empire by giving four, sometimes five, praetorian prefects responsibility for supervising large regions. In 324 Constantine began the building of a new city on the site of the Greek city of Byzantion, which he called New Rome but which is known as Constantinople in his honour, and in 330 he made it the capital of the Eastern half of the Empire. Because the more powerful of the co-Emperors (they returned after Constantine’s death) usually resided in the East, Constantine had virtually created a new capital for the Empire.
In 395 the Emperor Theodosius the Great died. Born in Spain, co-Emperor in the East from 379, the more powerful Emperor from 383, Theodosius was the last Emperor to exercise a considerable influence in both halves of the Empire. He intervened militarily in the West, and was sole Emperor for a few months before dying in Milan. Although he had arranged for his two sons to succeed him, his death is generally reckoned as the time when the two Empires went their separate ways. One son was adolescent, the other a child, both grew up lazy, incompetent and feeble. Theodosius’s adviser in the West, the Vandal general Stilicho, became Regent for the younger son. He tried several times to exercise authority in the East but the Regent there thwarted him and by 400 he had given up the attempt. The Empire was still thought of as one, Emperors would at times co-operate.
Even after the last Roman Emperor in the West had been dethroned in 476 and the West had become a collection of Germanic Kingdoms, most of the German Kings deeply respected Roman traditions and Roman law. Kings accepted Imperial offices from the Emperor in Constantinople and allowed the local Roman leadership to continue to exercise local control. But these were leftovers of an old order, and as each new generation of Germanic rulers came to power the sense of a wider Empire inevitably diminished. The Roman Empire had in reality been partitioned into a continuing Empire in the East and several barbarian Kingdoms in the West.
2. Extent. The Eastern Roman Empire during the 5th century formed a great arc around the eastern Mediterranean from the southern and eastern Balkans to Cyrenaica. To run through the changes made over a millennium, even in broad outline, would take too much space (for three areas, see articles on Byzantine Italy and Spain, and also ANATOLIA).
However some points should be made:-
The reign of the Emperor Justinian I (527-565) saw the Empire recover some of the western provinces. North Africa and the islands of the western Mediterranean were recovered from the Vandal Kingdom, destroyed in a few short months. Sicily, Italy and the northwestern Balkans were regained in a long and devastating war that destroyed the Ostrogothic Kingdom. Southernmost Spain was taken over from the Visigothic Kingdom. When Justinian died in 565, the Empire had gone a substantial way to restoring the Mediterranean Sea as a Roman lake.
In a very short while trouble erupted. In 568 the Lombards entered Italy and though Byzantine power survived in parts of Italy until the 11th century it never restored its rule to the entire peninsula. By the end of the century Avars and Slavs had entered the Balkans, raiding and plundering, and so far as the Slavs were concerned settling as well. The Empire held on to the important coastal towns but much of the interior was lost. The Slavs even temporarily penetrated into central Greece and the Peloponnese. The Empire later recovered ground, but was never entirely dominant over the Balkans again, its power and influence fluctuating with Slav power and influence. Particularly important until the 13th century was Bulgaria. If it waxed, the Empire waned in the Balkans. Only between 1018 and 1185 was there no Bulgarian state. The restored Byzantine Empire after 1261 had little trouble from Bulgaria, which had been gravely weakened by the Mongol invasion in 1242, but it faced competition from the Latin principalities in Greece, the independent-mindedness of various Greek princes and chieftains, and the rising power of Serbia, which reached its height in the second quarter of the 14th century. By the time Duan, Serbia’s greatest ruler, died in 1355, the Ottoman Turks had just crossed into the Balkans. They were eventually to establish a greater domination over the peninsula than the Byzantine Empire had done since the incursions of the Avars and the Slavs in the later 6th century.
The Lombards, Avars and Slavs had posed problems for the Empire in Europe. Early in the 7th century the Persians did the same for the Empire in Asia Minor and the Levant, but the Emperor Heraclius (610-41) forced them out, winning the decisive battle at Nineveh in 627. The last years of his reign saw the Arabs, with their new faith of Islam, burst out of the Arabian peninsula and begin the advance that swept Byzantine power from North Africa, Egypt and most of the Levant for ever. With these losses, the Roman Empire as the dominating power of the Mediterranean disappeared, though the Byzantine Empire remained a major power, which controlled the Straits by its possession of Thrace and Anatolia.
The next major disaster for the Empire came in the later 11th century, when the Turks took over most of Anatolia. It was a severe loss. In terms of territory, about half the Empire’s lands were gone, catastrophic in itself, but in military terms the loss was greater. The harsh terrain of much of Anatolia had been the best recruiting ground for the Byzantine armies. Byzantium looked set, if it did not disappear altogether, to join the ranks of the minor powers, but three considerable Emperors, all belonging to the Comnenus family, reigned for almost a century (1081-1180). The first of them, Alexius, sought aid from the west. The First Crusade certainly did not fulfil Alexius’s hopes – the Latin Crusaders recovered the Levant, including the recently lost Antioch, for themselves and not for the Greek Empire – but it helped in the recovery of most of coastal Anatolia and some of the interior.
The quarter of a century after the death of Manuel I in 1180 saw the return of instability to the Empire and ended in 1204 with its destruction through the diversion of the Fourth Crusade to Constantinople. The city was taken and a Latin Empire established. The new Empire was feeble from the beginning. Not only was it unable to secure for itself all of the provinces of the stricken Byzantine Empire, the Latin Emperor was not even in control of all his capital. The Venetians were allocated three-eighths of Constantinople and held this share and and their other new territories independently. Three Greek rulers emerged: in Epirus in the west, in Trebizond in the far east (much nearer to Georgia than to Constantinople), and in Nicaea, in northwestern and western Anatolia. By the 1240s the future lay with Nicaea, and in 1261 Michael VIII, the Emperor of Nicaea, recovered Constantinople and restored the Byzantine Empire.
Michael’s attention was turned on Europe, first because of the Latin princes and Greek chieftains that he wanted to bring back under imperial authority, but secondly because in the west appeared his greatest danger, the King of Sicily. The first he dealt with was Manfred, husband of an Epirote princess; then, after 1266, with Manfred’s supplanter, the cold, ruthless Charles of Anjou. Charles gained possession of the Albanian port, Dyrrachium (Durrës), which lay at the beginning of the Via Egnatia, the Roman road that led to Constantinople. Michael was right to fear Charles, but towards the end of his reign he realised that his neglect of Anatolia, partly the consequence of Turkish weakness and division, was mistaken. New determined opponents of the infidel, the ghazis, were emerging there; the Empire’s borders were being crossed and lands taken.
By the 330s little remained of Byzantine Anatolia and a new power had arisen among the Turks, the family of Osman or Uthman. In the early 350s the Ottomans crossed into Europe. By the 440s the Byzantine Empire consisted of Constantinople and its immediate Thracian environs, the islands of the northern Aegean and the greater part of the Peloponnese. The city was stormed in 1453, the islands passed to the Ottomans or the Venetians or the Genoese in the 1450s, the Peloponnese fell in two Turkish campaigns in 1458 and 1460.
3. Territorial divisions. In the later Roman Empire the PROVINCE and the DIOCESE, which grouped several provinces together, were the two types of circumscription into which the Empire was divided for the purposes of civil government. Diocletian (284-305), who increased the number of provinces and created the dioceses, took military responsibilities away from the governors and created separate military commands, the result of one of his principal concerns: to reduce the ability of the army to overturn the existing rulers.
As a result of the loss of territory in the disasters of the later 6th and 7th centuries, the armies of the Empire were settled in areas of Anatolia, each area being called a THEME. The themes emerge in the 7th century, though whether in the reign of Heraclius (610-41) or in that of his grandson, Constans II (641-68) is not sure. The commanders of the themes gradually took over responsibility for civil government in their areas as well, so the themes displaced the old Roman provinces. In the 11th century, some division of powers between military and civil authorities again took place, though power was consolidated again at provincial level under the Comneni (1081-1185). By the time the Empire was overthrown by the Fourth Crusade, the themes, much reduced in size, were controlled by the local landowners.