The Eastern Roman Empire 395–1453, with its capital at Constantinople (formerly Byzantium, modern Istanbul). It was the direct continuation of the Roman Empire in the East, and inherited many of its traditions and institutions.
Split from the West As the Roman Empire split into East and West, the Byzantine Empire emerged as its successor in the East and gradually transformed into a late medieval Greek state. The process began when Constantine I, the Great, founded Constantinople, or Nova Roma as the new, Christian, capital of the Roman Empire AD 330. The final division between East and West came after the death of Theodosius I 395 and the accession of his elder son, Arcadius, to the throne of the Eastern Empire marked its supremacy. Both parts suffered attacks from ‘barbarian’ tribes, mainly the Goths, Vandals, or Huns, but the East with its greater resources generally succeeded in deflecting their attacks to the west, where the last emperor was deposed 476.
The Empire's early struggles In its early stages, the Eastern Empire was troubled by intermittent war with the Persians and regular religious conflicts such as the upheavals caused by Nestorianism and the Monophysites. Various emperors' attempts to find a compromise doctrine succeeded only in alienating all parties, especially the papacy, and peace only came when Egypt, Syria, and Armenia, the areas where these doctrines were strongest, were lost to the Arabs.
Justinian I (527–65) embarked on grand schemes of reconquest and building which left the economy exhausted and his successors bore the consequences. The newly won provinces of Italy and Spain were quickly lost and the Balkans were overrun by Avars and Slavs, while to the east the Persian war resumed with particular violence. Heraclius (610–41) for a time remedied the military situation, only to see Egypt and Syria fall at once to the Arabs whose advance seemed irresistible. They were eventually checked only at Constantinople itself, where the victories of Constantine IV (678) and Leo III (718) over the besieging Arab forces can be compared with that of Charles Martel in France.
Consolidation In the period from Heraclius to Leo III (717–40), the Empire was reduced to southern Italy and Sicily, the Balkan peninsula, and Asia Minor. The loss of the Latin and Catholic west and the Monophysite Syrians and Egyptians left the Empire Greek and Orthodox, giving it its specifically Byzantine and medieval characteristics. Many of the Roman institutions vanished too: the cities, once so prominent, became forts or perished, as did their municipal traditions. Instead of the estates of the Late Roman Empire, there emerged a free peasantry. In the provinces the division of civil and military power was replaced by a military government in new units called themes. The central armies were largely broken up, and distributed round these, and recruited from the new class of peasants. In the 8th and 9th centuries the military situation stabilized.
The war with the Arabs degenerated into a series of raids and counter-raids, in which the Byzantines had several successes. In the Balkans, though Slav irruptions ceased and Byzantine authority began to expand, the Bulgars had established themselves south of the Danube and presented a potent threat. Italy, however, was left to the Lombards, leading the papacy to turn to the Franks for protection. The Byzantine theory of a universal empire was finally shattered by the coronation of Charlemagne as ‘Roman Emperor’ 800.
The ‘golden age’ The Byzantine Empire's armies in the east went from strength to strength, and under Nicephorus II Phocas and John I Zimisces (969–76) the war took on the atmosphere of a crusade. In the Balkans, Byzantine control was finally affirmed, despite repeated and costly wars with Bulgaria. The Russians too were brought within the imperial orbit. But relations with the West continued to deteriorate and there were several clashes with both the papacy and the Germans. Within the Empire, the thematic system of provincial government had become standard, but as offensive wars grew commoner, centralized armies re-emerged as did the division between civil and military functions.
Instability and collapse After the death of Basil II 1025, the system began to decay. Many of the peasant class, the basis of government revenue, were falling into poverty and their land was then snatched up by the increasingly powerful large landowners. Some of the larger landowners maintained their own private armies and increasingly came into conflict with the bureaucratic establishment in Constantinople as they tried to use their economic and military power to extort privileges from the emperors. Simultaneously, the state's army was falling into neglect due to overconfidence in the strength of the Empire while extravagance and mismanagement weakened imperial finances and the coinage had to be debased.
Eventually Alexius I Comnenus, a representative of the landowners, seized power. By then the survival of the Empire was in doubt, for it was caught between Turks from the east and Normans from Italy, and Alexius was only able to stabilize the frontiers when much territory had already been lost. He reformed the administration and finances, although he was unable to prevent regular revolts breaking out. Nonetheless the Empire prospered, until under the weak Angeli it collapsed altogether.
The Turks and Bulgarians again advanced, and the Empire began to fragment. The hostility between the Byzantines and the West sharpened, in particular during the crusades, and was encouraged by Italian dominance in trade. This enmity culminated in the sack of Constantinople by the Fourth Crusade 1204 and the creation of a short-lived Latin Empire. The Byzantines gradually regained much of their former territory, recapturing Constantinople itself 1261.
Fragmentation Although the Byzantine Empire was formally re-established, it never fully recovered. Three successor empires emerged – one based at Trebizond, one at Epirus, and one at Nicea, where a prosperous base was established from which Epirus and the Latin Empire were reconquered. In this period the Empire was dominated by the nobility, and took on a form similar to the feudal Latin Empire. Separatist tendencies flourished, and spread within the imperial family, and the country was repeatedly ravaged by civil wars. Arts and scholarship flourished though and Byzantine culture was an important factor in the Renaissance.
After 1261 the Empire's external situation grew increasingly severe. As the immediate threats from the West were warded off by Michael VIII Palaeologus, the Byzantines began to look to the West for aid against the Turks. Talks were held between the Orthodox and Catholic churches in an attempt to establish a pan-Christian front against the Turks and a union was finally negotiated in Florence 1439, but was subsequently rejected by most Byzantines. No significant help materialized, and the crusades of Nicopolis (1396) and Varna (1444) were decisively defeated. The Empire also became commercially dependent on Venice and Genoa, and hence was the main casualty in their frequent conflicts.
Rise of the Ottomans In the Balkans, the Serbian Empire eclipsed the Bulgarians, but, there as in Asia the Ottoman Turks swept all before them. The Empire's Asian provinces were neglected and lost; Nicea was taken 1331, and in 1354 the Turks crossed into Europe. By 1389 they had subdued Serbia and Bulgaria, and the Byzantines were forced to acknowledge their sovereignty. Sultan Bajazet's defeat by Tamerlane 1402 gave a temporary reprieve, but the Ottomans soon recovered. Constantinople finally fell to Muhammad II 29 May 1453 and the Byzantine Empire came to an end.