|330||Constantine I makes Constantinople his capital.|
|527||Justinian I becomes Emperor.|
|532-537||Justinian builds the church of Hagia Sophia|
|1054||The Church in Constantinople breaks with the Church in Rome|
|1204||Constantinople is captured by crusaders|
|1261||Constantinople is liberated by the Byzantine emperor Michael Palaeologus.|
|1453||Ottoman Turks take Constantinople. End of Byzantine Empire|
The division of the Empire began with the Tetrarchy (quadrumvirate) in the late 3rd century AD with Emperor Diocletian, as an institution intended to more efficiently control the vast Roman empire. He split the empire in half, with two emperors ruling from Italy and Greece, each having a co-emperor of their own. This division continued into the 4th century, when the emperor Constantine the Great rebuilt Byzantium (today's Istanbul) in AD 330. He renamed it Constantinople and made it the capital of his half of the empire. He gradually became the sole ruler of the empire, but the administration was now centred on his new capital. Constantine was also the first Christian emperor. Although the empire was not yet "Byzantine" under Constantine, Christianity would become one of the defining characteristics of the Byzantine Empire, as opposed to the pagan Roman Empire.
Another defining moment in the history of Roman/Byzantine Empire was the Battle of Adrianople in 378. This defeat, along with the death of Emperor Valens, is one possible date for dividing the ancient and medieval worlds. The Roman empire was divided further by Valens' successor Theodosius I (also called "the great"), who had ruled both beginning in 392. In 395 he gave the two halves to his two sons Arcadius and Honorius; Arcadius became ruler in the East, with his capital in Constantinople, and Honorius became ruler in the west, with his capital in Milan. At this point it is common to refer to the empire as "Eastern Roman" rather than "Byzantine."
Although the empire was still considered Roman, in reality the general prevailing cultural identity of the Eastern Roman Empire was Greek. Greek was not only the everyday language, but also the language of the church, of the literature and of all commercial transactions. The empire was a multinational state, including Greeks, Armenians, Jews, Egyptians, Syrians, Illyrians, and Slavs, but its Greek culture radiated from large centers of Hellenism such as Constantinople, Antioch, Ephesus, Thessalonika and Alexandria. Though it was not as pronounced at this time, the Eastern Empire was developing its own style of Christianity, under such scholars as John Chrysostom.
The Eastern Empire was largely spared the difficulties of the west in the 3rd and 4th centuries, in part because urban culture was better established there and the initial invasions were attracted to the wealth of Rome. Throughout the 5th century various invasions conquered the western half of the empire, but at best could only demand tribute from the eastern half. Theodosius II expanded the walls of Constantinople, leaving the city impenetrable to barbarian attacks. Zeno I ruled the east as the empire in the west finally collapsed in 476. Zeno negotiated with the Goths, ending their threats to the east but leaving them in control of the west.
The 6th century saw the beginning of the conflicts with the Byzantine Empire's traditional early enemies, the Persians, Slavs, and Bulgars. Theological crises, such as the question of Monophysitism, also dominated the empire. However, the Eastern Empire had not forgotten its western roots. Under Justinian I, and the brilliant general Belisarius, the empire even regained some of the lost Roman provinces in the west, conquering much of Italy, north Africa, and Spain. Justinian updated the ancient Roman legal code in the new Corpus Juris Civilis, although it is notable that these laws were still written in Latin, a language which was becoming archaic and poorly understood even by those who wrote the new code. Under Justinian's reign, the Church of Hagia Sophia was constructed in the 530s. This church would become the centre of Byzantine religious life and the centre of the still-developing Eastern Orthodox form of Christianity.
Justinian left his successors an empty treasury, however, and they were unable to deal with the sudden appearance of new invaders on all fronts. The Lombards seized Northern Italy, the Slavs overwhelmed much of the Balkans, and the Persians invaded and conqured the eastern provinces. These were recovered by the emperor Heraclius, but the unexpected appearance of the newly converted and united Muslim Arabs took Heraclius by surprise, and the southern provinces were all overrun. Mesopotamia, Syria and Egypt were permanently incorporated into the Muslim Empire in the 7th century.
What the empire lost in territory, though, it made up in uniformity. Heraclius fully Hellenized the empire by making Greek the official language, and he took the title Basileus ("king") instead of the old Roman term Augustus. The empire was by now noticeably different in religion than the former imperial lands in western Europe, although the southern Byzantine provinces differed significantly from the north in culture and practiced monophysite (rather than Orthodox) Christianity. The loss of the southern provinces to the Arabs made Orthodoxy stronger in the remaining provinces. Heraclius divided the empire into a system of military provinces called themes to face permanent assault, with urban life declining outside the capital while Constantinople grew to become the largest city in the world. Attempts by the Arabs to conquer Constantinople failed in the face of the Byzantines' superior navy and their monopoly of the still mysterious incendiary weapon Greek fire. After repelling the initial Arab assault, the empire began to recover.
The 8th century was dominated by the controversy over iconoclasm. Icons were banned by Emperor Leo III, leading to revolts by iconophiles within the empire. Thanks to the efforts of Empress Irene, the Second Council of Nicaea met in 787 and affirmed that icons could be venerated but not worshipped. Irene also attempted a marriage alliance with Charlemagne, which would have united the two empires, but these plans came to nothing. The iconoclast controversy returned in the early 9th century, but they were restored once more in 843. These controversies did not help the disintegrating relations with the Roman Catholic Church and the Holy Roman Empire, which were both beginning to gain more power of their own.
The empire reached its height under the Macedonian emperors of the late 9th, 10th and early 11th centuries. During these years the Empire held out against pressure from the Roman church to remove the patriarch Photius, and gained control over the Adriatic Sea, parts of Italy, and much of the land held by the Bulgarians. The Bulgarians were completely defeated by Basil II in 1014. The Empire also gained a new ally (yet sometimes also an enemy) in the new Russian state in Kiev, from which the empire received an important mercenary force, the Varangian Guard.
Like Rome before it, though, Byzantium soon fell into a period of difficulties, caused to a large extent by the growth of the landed aristocracy, which undermined the theme system. Facing its old enemies, the Holy Roman Empire and the Abbasid caliphate, it might have recovered, but around the same time new invaders appeared on the scene who had little reason to respect its reputation - the Normans, who conquered Italy, and the Seljuk Turks, who were mainly interested in defeating Egypt but still made moves into Asia Minor, the main recruiting ground for the Byzantine armies. With the defeat at Manzikert of emperor Romanus IV in 1071 by Alp Arslan, sultan of the Seljuk Turks, most of that province was lost. The final split between the Roman and Orthodox churches occurred at this time as well, with their mutual excommunication in 1054.
The last few centuries of Byzantine life were brought by a usurper, Alexius Comnenus, who began to reestablish an army on the basis of feudal grants (pronoia) and made significant advances against the Seljuk Turks. His plea for western aid against the Seljuk advance brought about the First Crusade, which helped him reclaim Nicaea but soon distanced itself from imperial aid. Later crusades grew increasingly antagonistic. Although Alexius' grandson Manuel I Comnenus was a friend of the Crusaders, neither side could forget that the other had excommunicated them, and the Byzantines were very suspicious of the intentions of the Roman Catholic Crusaders who continually passed through their territory. The Germans of the Holy Roman Empire and the Normans of Sicily and Italy continued to attack the empire in the 11th and 12th centuries. The Italian city states, who had been granted trading rights in Constantinople by Alexius, became the targets of anti-Western sentiments as the most visibly example of Western "Franks" or "Latins." The Venetians were especially disliked, even though their ships were the basis of the Byzantine navy. To add to the empire's concerns, the Seljuks remained a threat, defeating Manuel at Myriokephalon in 1176.
Frederick Barbarossa attempted to conquer the empire during the Third Crusade, but it was the Fourth Crusade that had the most devastating effect on the empire. Although the intent of the crusade was to conquer Egypt, the Venetians took control of the expedition, and under their influence the crusade captured Constantinople in 1204. As a result a short-lived feudal kingdom was founded, (the Latin Empire) and Byzantine power was permanently weakened.
Three Byzantine successor states were left - the Empire of Nicaea, Epirus, and Trebizond. The first, controlled by the Palaeologan dynasty, managed to reclaim Constantinople in 1261 and defeat Epirus, reviving the empire but giving too much attention to Europe when the Asian provinces were the primary concern. For a while the empire survived simply because the Muslims were too divided to attack, but eventually the Ottomans overran all but a handful of port cities. The empire appealed to the west for help, but they would only consider sending aid in return for reuniting the churches. Church unity was considered, and occasionally accomplished by law, but the Orthodox citizens would not accept Roman Catholicism. Some western mercenaries arrived to help, but many preferred to let the empire die, and did nothing as the Ottomans picked apart of the remaining territories.
Constantinople was initially not considered worth the effort of conquest, but with the advent of cannons, the walls, which had been impenetrable except by the Crusaders for over 1000 years, no longer offered protection from the Ottomans. The Fall of Constantinople finally came after a two-year siege by Mehmed II on May 29, 1453. By the end of the century the remaining cities, such as Trebizond and Mistra, had also fallen.
The Byzantine empire played an important role in the transmission of classical knowledge to the Islamic world. Its most lasting influence, though, lies in its church. Early Byzantine missionary work spread Orthodox Christianity to various Slavic peoples, and it is still predominant among them and the Greeks. The start and end dates of the capital's independence, 395 to 1453, were originally the defined bounds of the Middle Ages.
See also List of Byzantine Empire-related topics, Roman Empire, Roman Emperors, Byzantine Emperors, Latin Empire, Empire of Nicaea, Byzantine currency, Byzantine architecture and Byzantine aristocracy and bureaucracy.