The Byzantine Empire was the eastern half of the Roman Empire, centered on Constantinople, which survived the fall of the western empire in AD 476 and endured until 1453. Its people called themselves Romans. Its emperors claimed the whole Roman inheritance. Historians call it Byzantine, after Byzantion, the old Greek name of Constantinople, to mark how much it changed: Greek-speaking, Christian, and centered on a single great city. For nearly a thousand years it was the wall between Europe and the invasions from the east, and the bridge that carried Roman law and Greek learning to the modern world.
The Byzantine Empire began as a decision. In AD 330, Constantine I founded a new capital on the Bosporus, on the site of the old Greek town of Byzantion. The location was a strategist's dream: a peninsula guarded by water on three sides, a harbor, the Golden Horn, that could be chained shut, and a position astride the trade routes between Europe and Asia. Constantinople grew with astonishing speed. Within a century it was the largest city in the Mediterranean world, with a Senate, a hippodrome, aqueducts, and walls that would hold for a thousand years.
The east had advantages the west lacked. It was richer: Egypt grew the grain, Anatolia paid the taxes, and the trade routes of the eastern Mediterranean ran through its ports. It was more urban, with old Greek cities that had governed themselves for centuries. And it was easier to defend, with shorter frontiers and a capital that could be supplied by sea when enemies cut the land routes. When the western empire fell apart in the fifth century, the east did not follow. It paid off invaders, hired them, and outlasted them. Theodosius II built the great land walls of Constantinople in the 410s, and those walls, layered and towered, would turn back siege after siege.
What made the east Roman was not language. It was law, administration, and the imperial idea. The emperor in Constantinople wore the purple, commanded the armies, and claimed to rule the whole Roman world, even the parts now ruled by Germanic kings. The Senate of Constantinople, the bureaucracy, the tax system, and the legal codes were all Roman institutions, carried east and continued. The people of the empire called themselves Rhomaioi, Romans. The name Byzantine was invented much later, by scholars who wanted a label for the empire's Greek and Christian centuries. It is a useful label, but it hides the continuity: this was Rome, still standing.
The reign of Justinian I, from 527 to 565, was the empire's great gamble. Justinian was a provincial who became emperor through talent and marriage to Theodora, a former actress who became one of the most formidable empresses in history. Together they faced the Nika Riot of 532, when Constantinople's racing factions turned a sporting rivalry into a full-scale revolt. Theodora refused to flee, the revolt was crushed, and tens of thousands died in the hippodrome. The regime survived, and Justinian turned to his grand project: the reconquest of the west.
His general Belisarius led armies that retook North Africa from the Vandals in 533 and 534, and then invaded Italy, taking Rome and Ravenna from the Ostrogoths in a war that dragged on for two decades. At its height, Justinian's empire held much of the Mediterranean shore, from southern Spain to Egypt to Italy. The reconquest was real, and it was ruinous. The wars exhausted the treasury, devastated Italy, and left the empire overextended just as a new enemy, the plague, arrived. The plague of 541, which struck Constantinople and spread across the Mediterranean, killed a large share of the population and hollowed out the tax base. Justinian's empire was the largest it would ever be, and it could not afford itself.
Justinian's most durable achievement was not conquest but law. His jurists, led by Tribonian, compiled centuries of Roman law into the Corpus Juris Civilis, the body of civil law: the Code, the Digest, and the Institutes. When the west rediscovered this compilation in the Middle Ages, it became the foundation of civil law across continental Europe. The same reign built Hagia Sophia, consecrated in 537, the great church whose dome seemed, in the words of contemporaries, to hang from heaven. The building still stands in Istanbul, a mosque today, and it remains the empire's most famous monument.
The seventh century was the empire's darkest hour. The Persians, under Khosrow II, overran Syria, Palestine, and Egypt, and carried off the True Cross from Jerusalem. The Avars and Slavs pressed into the Balkans. Constantinople itself was besieged. Then Heraclius, who took the throne in 610, rebuilt the army and led a counteroffensive deep into Persian territory, winning at Nineveh in 627 and recovering the lost provinces and the Cross. The victory was total, and it was empty: both empires had bled themselves white, and a new force was rising in Arabia.
Within a decade of Heraclius's triumph, Arab armies carried Islam out of Arabia and took Syria, Palestine, and Egypt from the empire. The loss of Egypt's grain and Syria's taxes cut the empire's revenues by more than half. The empire shrank to Anatolia, parts of Greece, and Constantinople itself. It survived by reinventing itself. The theme system divided Anatolia into military districts where soldiers held land in exchange for service. The navy, armed with Greek fire, a secret incendiary weapon, held the sea. The great siege of 717 to 718, when Arab armies and fleets attacked Constantinople, failed against the walls, the fire, and a hard winter. The empire lived.
The eighth century brought the iconoclast controversy, the fight over religious images. Emperors from Leo III onward ordered icons destroyed, arguing that images were idolatry. Monasteries, monks, and much of the population resisted. The controversy lasted more than a century, with restorations and reversals, and it split the empire from the papacy in Rome, which defended images. Iconoclasm was also about power: icons, monasteries, and relics were wealth and influence, and the emperors wanted both under imperial control. The icons were finally restored in 843, on the feast still celebrated as the Triumph of Orthodoxy. The controversy left a church that was more firmly under the emperor, and a west that was drifting toward its own path.
From the ninth to the eleventh centuries, the empire recovered and reached a second peak. The Macedonian dynasty, founded by Basil I in 867, presided over a golden age of expansion, law, and culture. The empire retook territory in the Balkans and the east, pushed the frontiers back, and restored its finances. Under Basil II, called the Bulgar-Slayer, the empire destroyed the Bulgarian state in a long war that ended in 1018, and for a generation the empire was again the dominant power of the eastern Mediterranean.
This was also the empire's cultural high point. Byzantine scholars preserved the classics of Greek literature, philosophy, and science, copying manuscripts that would otherwise have been lost. Byzantine art, the mosaics, the icons, the illuminated manuscripts, set the visual language of Orthodox Christianity for centuries. Byzantine missionaries, Cyril and Methodius, carried Christianity and a new alphabet, Cyrillic, to the Slavs, and the conversion of Rus under Vladimir in 988 tied the future Russia to Constantinople's church. The empire's diplomacy was famously subtle: it used titles, marriages, gifts, and threats to manage its neighbors, and its gold coin, the solidus, was the most trusted currency in the medieval world.
The same period carried the seeds of division. In 1054, the mutual excommunication of the patriarch of Constantinople and the pope's legates formalized the schism between Eastern Orthodoxy and Roman Catholicism. The split had deep roots: different languages, different customs, and a long argument over whether the pope held authority over the whole church. The schism of 1054 did not end relations overnight, but it marked the moment when the two Christian worlds began to see each other as separate. Then, in 1071, the empire suffered a catastrophe at Manzikert, where the Seljuk Turks defeated and captured the emperor Romanos IV. Anatolia, the empire's heartland, began to slip away.
Manzikert brought the Crusades. The emperor Alexios I appealed to the west for help against the Turks, and the appeal produced the First Crusade in 1096, an armed pilgrimage that retook Jerusalem and carved crusader states out of the Levant. The crusaders were useful and dangerous in equal measure. They fought the Turks, and they also fought over Byzantine territory, and the alliance was poisoned by mutual suspicion. The empire recovered much of western Anatolia under the Komnenian emperors, Alexios, John II, and Manuel I, and for a century Constantinople was again a great power, rich, cultured, and confident.
The Fourth Crusade destroyed that recovery. In 1204, a crusader army, diverted by Venetian politics and debt, turned on Constantinople itself. The crusaders stormed the city, sacked it for three days, and carved the empire into Latin principalities. The sack was one of the great crimes of medieval history: churches stripped, libraries scattered, and the city's wealth carried west. The empire survived in exile, in Nicaea, Epirus, and Trebizond, but the damage was permanent. The great city was broken, its population scattered, and its authority shattered. The Byzantines themselves blamed the Latins for the empire's long decline, and the memory of 1204 poisoned relations between east and west for centuries.
The empire was restored in 1261, when the Nicaean emperor Michael VIII retook Constantinople. But it was a shadow. The city was depopulated and ruined. The provinces were gone or contested. The Turks pressed into Anatolia. The Serbs and Bulgarians pressed in the Balkans. The empire became a city-state with a few outposts, surviving by diplomacy, by playing its enemies against each other, and by the sheer prestige of the imperial name. Its scholars and artists still produced remarkable work, and its church still commanded loyalty across the Orthodox world, but the material base of empire was gone.
The end came on 29 May 1453. The Ottoman sultan Mehmed II, called the Conqueror, brought a great army and enormous cannon to Constantinople. The emperor Constantine XI defended the city with a small force of Greeks, Genoese, and Venetians. The walls, which had held for a thousand years, could not hold against gunpowder. The city fell. Constantine XI died in the fighting, and his body was never identified. Mehmed entered Hagia Sophia, which became a mosque, and made Constantinople the capital of his own empire. The Byzantine Empire was over.
The afterlife was long. The scholars who fled the falling city carried Greek manuscripts west, and their arrival fed the Renaissance in Italy. The idea of the Christian empire passed to Moscow, where the grand princes married into the last imperial family and claimed the title of Third Rome. The Orthodox Church, centered on the patriarchate in Constantinople, survived under Ottoman rule and kept the Byzantine liturgy, art, and law alive. The empire's legal codes, its diplomacy, and its military manuals were studied for centuries.
The Byzantine story is often told as a long decline, a thousand years of slow failure. That is the wrong shape. The empire survived because it adapted: from Roman to Greek, from Mediterranean to Anatolian, from universal empire to city-state, and it kept adapting for eleven centuries. It guarded Europe's southeastern door, preserved Greek learning and Roman law, and built a civilization that was neither western nor eastern but its own. When it fell, Europe lost a neighbor it had often despised and always needed.
- 330: Constantine I founds Constantinople as the new capital.
- 410s: Theodosius II builds the great land walls of Constantinople.
- 476: The western empire ends; the east continues.
- 527 to 565: Reign of Justinian I, reconquest and the Corpus Juris Civilis.
- 532: The Nika Riot shakes Constantinople and is crushed.
- 537: Hagia Sophia is consecrated.
- 541: Plague strikes Constantinople and spreads across the Mediterranean.
- 610 to 641: Reign of Heraclius, who defeats Persia and then loses Syria and Egypt to the Arabs.
- 717 to 718: The great Arab siege of Constantinople fails.
- 726 to 843: The iconoclast controversy, with intervals, divides the empire.
- 867: Basil I founds the Macedonian dynasty.
- 988: Vladimir of Rus accepts baptism, tying Rus to Constantinople.
- 1054: Mutual excommunications formalize the schism between East and West.
- 1071: The Battle of Manzikert: the Seljuk Turks defeat the empire and open Anatolia.
- 1096: The First Crusade sets out after the appeal of Alexios I.
- 1204: The Fourth Crusade sacks Constantinople.
- 1261: Michael VIII retakes Constantinople and restores the empire.
- 1453: Constantinople falls to Mehmed II and the empire ends.
Constantine I (272 to 337) The emperor who founded Constantinople, favored Christianity, and moved the center of power east. His decisions shaped the next thousand years.
Theodosius II (401 to 450) The emperor who built the great land walls of Constantinople in the 410s, the fortifications that guarded the city for a thousand years.
Justinian I (483 to 565) The emperor of reconquest and law. His armies retook North Africa and Italy, and his jurists compiled the Corpus Juris Civilis, the foundation of civil law.
Theodora (about 500 to 548) Empress and wife of Justinian, a former actress who became a formidable political partner. Her refusal to flee during the Nika Riot saved the regime.
Belisarius (about 505 to 565) Justinian's great general, who retook North Africa from the Vandals and campaigned in Italy. One of the most celebrated commanders of the ancient world.
Heraclius (about 575 to 641) The emperor who rebuilt the army, defeated Persia, and then watched Arab armies take Syria, Palestine, and Egypt.
Leo III (about 685 to 741) The emperor who held Constantinople against the Arab siege of 717 to 718 and began the iconoclast policy.
Basil II (958 to 1025) Called the Bulgar-Slayer, the emperor who destroyed the Bulgarian state and brought the empire to its second peak.
Anna Komnene (1083 to 1153) Princess and historian, author of the Alexiad, the history of her father Alexios I and one of the great works of medieval history.
Alexios I Komnenos (1048 to 1118) The emperor whose appeal for help against the Turks helped launch the First Crusade, and who rebuilt the empire after Manzikert.
Constantine XI (1405 to 1453) The last emperor, who died defending Constantinople against Mehmed II in 1453.
The Byzantine legacy is everywhere once you look for it. Roman law, preserved and codified in Constantinople, became the basis of civil law across Europe. The Cyrillic alphabet, carried to the Slavs by Byzantine missionaries, is still used by hundreds of millions of people. Orthodox Christianity, its liturgy, its icons, and its music, descends directly from the church of Constantinople. The idea of a Christian empire, of a ruler anointed by God, passed from Constantinople to Moscow and to the monarchies of Europe.
The empire also preserved what the west lost. Byzantine scholars copied and studied the Greek classics, and when the empire fell, their manuscripts and their learning fed the Renaissance. Byzantine diplomacy, with its titles, ceremonies, and careful management of neighbors, became a model for later courts. Byzantine art set the visual language of the Orthodox world, from the mosaics of Ravenna to the churches of Russia.
The honest balance is this: the empire was often rigid, often cruel, and often blind to the west it claimed to lead. Its court was a byword for intrigue, and its emperors sometimes chose theology over strategy. Yet it held a frontier for a thousand years, kept a city alive that was the largest in the Christian world, and carried Roman law and Greek learning through centuries when both could have been lost. Magna Bureau tells the story whole, because the empire that guarded Europe's door deserves more than a footnote.
- John Julius Norwich, A Short History of Byzantium, 1997.
- Judith Herrin, Byzantium: The Surprising Life of a Medieval Empire, 2007.
- Cyril Mango, editor, The Oxford History of Byzantium, 2002.
- Procopius, The Secret History and The Wars, written sixth century AD.
- Anna Komnene, The Alexiad, written twelfth century AD.
- Warren Treadgold, A History of the Byzantine State and Society, 1997.
- Dumbarton Oaks Research Library and Collection, Byzantine studies resources.
- Encyclopaedia Britannica, entries on the Byzantine Empire, Justinian I, and Constantinople.
- Metropolitan Museum of Art, Heilbrunn Timeline of Art History, entries on Byzantium.
- British Museum, collections and resources on Byzantium.