Start date Given the significant overlap in historiographical
periodisations of "
Late Roman history", "
late antiquity", and "Byzantine history", there is no consensus on a foundation date for the Byzantine Empire. Scholarship with links to Greece or
Eastern Orthodoxy has customarily placed it in the early 300s. The growth of the study of "late antiquity" has led to some historians setting a start date in the seventh or eighth centuries. Others believe a "new empire" began during changes AD. Geoffrey Greatrex believes that it is impossible to precisely date the foundation of the Byzantine Empire.
Pre-518: Constantinian, Theodosian, and Leonid dynasties under the
Tetrarchy system established by
Diocletian|alt=A map showing the division of the Roman empire Between the 3rd and 1st centuriesBC, the
Roman Republic established
hegemony over the
eastern Mediterranean, while
its government developed into the one-person rule of
an emperor. The
Roman Empire enjoyed a period of
relative stability until
the 3rd century AD, when external threats and internal crises caused it to splinter, as regional armies acclaimed their generals as "
soldier-emperors". One of these,
Diocletian (), recognised that the state was too big to be ruled by a single person. He instituted the
Tetrarchy, a system which divided the empire into eastern and western halves. The Tetrarchy quickly failed, but the division of the empire proved an enduring concept.
Constantine I () secured absolute power in 324. Over the next six years, he rebuilt the city of Byzantium as a new
capital that he called "New Rome" (later named
Constantinople). The old capital
Rome was farther from the prosperous eastern provinces and in a less strategically important location; its esteem had already been somewhat lessened in the eyes of the "soldier-emperors", who ruled from the frontiers, and of the empire's population.
Having been granted citizenship, they considered themselves just as Roman as those in the city of Rome. He continued reforms of the empire's military and civil administration and instituted the
gold solidus as a stable currency. He
favoured Christianity and became an opponent of paganism. Constantine's dynasty prioritised
a lengthy conflict against the comparably powerful
Sasanid Persia and ended in 363 with the death of his nephew
Julian. The reign of the short
Valentinianic dynasty, marked by
wars against the Goths, religious debates, and anti-corruption campaigns, ended in the East with the death of
Valens at the
Battle of Adrianople in 378. Valens's successor,
Theodosius I (), secured peace in the east by allowing the
Goths to settle in Roman territory; he also twice intervened in the western half, defeating the usurpers
Magnus Maximus and
Eugenius in 388 and 394, respectively. He
actively condemned paganism, confirmed the primacy of
Nicene Orthodoxy over
Arianism in the East, and established
Christianity as the Roman state religion. He was the last emperor to rule both the western and eastern halves of the empire. After his death, the West was destabilised but the East thrived due to the civilian administrators who continued to hold power.
Theodosius II () largely left the rule of the East to officials such as
Anthemius, who constructed the
Theodosian Walls. Constantinople had now entrenched itself as the empire's capital. Aside from Constantinople's walls, Theodosius' reign was also marked by the compilation of the
Codex Theodosianus and the theological dispute over
Nestorianism (a doctrine later deemed
heretical). His reign also saw the arrival of
Attila's
Huns, who ravaged the
Balkans, leading to a large
tribute being exacted from the eastern empire. Attila switched his attention to the
rapidly-deteriorating western empire, and his people fractured after his death in 453. Later,
Leo I () failed in his
468 attempt to reconquer the
West. The warlord
Odoacer deposed
Romulus Augustulus in 476 and after the assassination of his titular successor
Julius Nepos in 480, abolished the office of western emperor. Through a combination of fortune and good political decisions, the Eastern Empire never experienced rebellious barbarian vassals or rule by barbarian warlords—the problems which ensured the downfall of the West.
Zeno () convinced the problematic
Ostrogoth king
Theodoric to take control of Italy from Odoacer; dying when the empire was at peace, he was succeeded by
Anastasius I (). His belief in
monophysitism brought occasional issues, but Anastasius was a capable administrator and instituted successful financial reforms including the abolition of the
chrysargyron tax. He was the first emperor since Diocletian not to face any serious problems affecting the empire during his reign.
518–717: Justinian and Heraclian dynasties The reign of
Justinian I was a high point in east Roman history. Following his accession in 527, the legal code was rewritten as the
Corpus Juris Civilis, which streamlined Roman law across the empire; he reasserted imperial control over religion and morality through purges of pagans, heretics, and other "deviants"; and having ruthlessly subdued
the 532 Nika revolt he rebuilt much of Constantinople, including the
Hagia Sophia. Justinian I took advantage of the confusion, following Theoderic the Ostrogoth's death, to attempt the reconquest of Italy. The
Vandal Kingdom in North Africa
was subjugated in late 533 by the general
Belisarius, who
then invaded Italy; the
Ostrogothic Kingdom mostly ended in 554. In the 540s, Justinian began to suffer reversals on multiple fronts. Capitalising on Constantinople's preoccupation with the West,
Khosrow I of the Sasanian Empire invaded Byzantine territory and sacked
Antioch in 540.
A devastating plague killed a large proportion of the population and severely reduced the empire's social and financial stability. The most difficult period of the Ostrogothic war, against their king
Totila, came during this decade; while divisions among Justinian's advisors undercut the administration's response. He also did not fully heal the divisions in
Chalcedonian Christianity, as the
fifth ecumenical council failed to make a real difference. Justinian died in 565; his reign was more successful than any other emperor, yet he left behind an unstable empire.
Justin II () inherited an empire stretched thin both financially and territorially. He was soon at war on many fronts. Fearing the aggressive
Avars, the
Lombards conquered much of northern Italy by 572. The
Sasanian wars restarted in the same year, and would not conclude until 591; by this time, the Avars and
Slavs had repeatedly invaded the Balkans, causing great instability.
Maurice campaigned extensively in the region during the 590s, and although he re-established Byzantine control up to the
Danube, he pushed his troops too far in 602—they mutinied, proclaimed an officer named
Phocas as emperor, and executed Maurice. The Sasanians seized their moment and
reopened hostilities; Phocas was unable to cope and soon faced
a major rebellion led by
Heraclius. Phocas lost Constantinople in 610 and was executed; this destructive civil war accelerated the empire's decline. of Constantinople, very important during the
717–718 siege|alt=A photograph of a large double-layered fortification. Under
Khosrow II, the Sassanids occupied the
Levant and Egypt and advanced into Asia Minor, and the Avars and Slavs raided in the Balkans. The Empire's control of Italy also weakened. After successfully repelling
a siege of Constantinople in 626, Heraclius won a decisive victory at the
Battle of Nineveh, eventually defeating the Sassanids later that year. The triumph would prove short-lived. The
Arab conquests soon saw the
conquest of the Levant,
Egypt, and
the Sassanid Empire by the newly formed Arab
Rashidun Caliphate. By Heraclius' death in 641, the empire had been severely reduced economically and territorially—the loss of the wealthy eastern provinces had deprived the empire of as much as three-quarters of its revenue. The next century is poorly documented.
Arab raids into Asia Minor started quickly, and the Empire responded by holding fortified centres and avoiding battle wherever possible. Although Anatolia was invaded annually, it avoided permanent Arab occupation. The outbreak of the
First Fitna in 656 gave the Empire breathing space, which it used sensibly: some order was restored in the Balkans by
Constans II () following his administrative reorganisation which over time evolved into the "
theme system", a structure that allocated troops to defend specific provinces.
Constantine IV () repelled the Arab efforts to
capture Constantinople in the 670s using
Greek fire, but suffered a reversal against the
Bulgars, who soon established
an empire in the northern Balkans. Nevertheless, he had done enough to secure the empire's position, especially as the
Umayyad Caliphate was undergoing
another civil war. Beginning in 695, when Constantine's son
Justinian II was first deposed, the empire entered an
era of political instability that lasted for the next 22 years. While Justinian had stabilised the situation with the divided Arabs, the threat of the reconstituted caliphate was met by
Leo III when he
repelled the 717–718 siege, the first serious challenge against Arab expansion.
718–867: Isaurian, Nikephorian, and Amorian dynasties (left) and his son and heir,
Constantine V (right)|alt=Two gold coins, each depicting a man The emperors Leo III () and
Constantine V () were very effective leaders, both in government and warfare. They withstood continued Arab attacks, as well as civil war and natural disasters. Constantine's success reestablished the state as a major regional power. Leo's reign produced the
Ecloga, a code of law that evolved that of Justinian I. He also continued to reform the theme system in order to lead offensive campaigns against the Muslims, culminating in
a notable victory in 740. Constantine overcame an early civil war against his brother-in-law
Artabasdos, created stability against the new
Abbasid Caliphate,
campaigned successfully against the Bulgars, and continued to make administrative and military reforms. Due to both emperors' support for the
Byzantine Iconoclasm, where the use of
religious icons was banned, they were later vilified by biased authors, creating issues that continue to impact modern scholarship; Constantine's reign also saw the loss of
Ravenna to the
Lombards, and the beginning of a split from the
Roman papacy. In 780, Empress
Irene assumed power as regent for her son
Constantine VI. Although she was a capable administrator who temporarily resolved the iconoclasm controversy, the empire was destabilised by her conflict with her son. The Bulgars and Abbasids inflicted numerous defeats on the Byzantine armies, and the papacy crowned
Charlemagne as Roman emperor in 800. In 802, the unpopular Irene was overthrown by
Nikephoros I; he reformed the empire's administration but died
in battle against the Bulgars in 811. Military defeats and societal disorder, especially the resurgence of iconoclasm, characterised the next eighteen years. Stability was somewhat restored during the reign of
Theophilos (). He capitalised on economic growth to complete construction programmes, including rebuilding the
sea walls of Constantinople, overhaul provincial governance, and wage inconclusive campaigns against the Abbasids. After his death, his empress
Theodora, ruling on behalf of her son
Michael III, permanently extinguished the iconoclastic movement; the empire prospered under their sometimes-fraught rule. Michael was posthumously vilified by historians loyal to the dynasty of his successor
Basil I, who had him assassinated in 867 and was credited with his predecessor's achievements.
867–1081: Macedonian and Doukas dynasties Basil I () continued Michael's policies. His armies campaigned with mixed results in Italy but
defeated the
Paulicians of Tephrike. His successor
Leo VI () compiled and propagated a huge number of written works. These included the
Basilika, a Greek translation of Justinian I's legal code incorporating over 100 new laws created by Leo; the
Tactica, a military treatise; and the
Book of the Eparch, a manual on Constantinople's trading regulations. In non-literary contexts Leo was less successful: the empire
lost in Sicily and
against the Bulgarians, and he provoked theological scandal by marrying four times in an attempt to father a legitimate heir. The early reign of this heir,
Constantine VII, was tumultuous, as his mother
Zoe, his uncle
Alexander, the patriarch
Nicholas, the powerful
Simeon I of Bulgaria, and other influential figures jockeyed for power. In 920, the admiral
Romanos I used his fleet to secure power, crowning himself and demoting Constantine to the position of junior co-emperor. His reign, marked by
the end of the war against Bulgaria and successes in the east under the general
John Kourkouas, ended in 944 due to the machinations of his sons, whom Constantine then usurped. Constantine's ineffectual sole rule has often been construed as
the zenith of Byzantine learning, but the works compiled were largely intended to legitimise and glorify the emperor's
Macedonian dynasty.
His son and successor died young; under two soldier-emperors,
Nikephoros II () and
John I Tzimiskes (), the army claimed numerous military successes, including the
conquest of Cilicia and
Antioch, and a
victory against Bulgaria and the Kievan Rus' in 971. John in particular was an astute administrator who reformed military structures and implemented effective fiscal policies. 's death in 1025 After John's death, Constantine VII's grandsons
Basil II and
Constantine VIII ruled jointly for half a century, although the latter exercised no real power. Their early reign was occupied by conflicts against two prominent generals,
Bardas Skleros and
Bardas Phokas, which ended in 989 after the former's death and the latter's submission, and a power struggle against the eunuch
Basileios, who was dismissed in 985. Basil, who never married or had children, subsequently refused to delegate any authority: he sidelined the military establishment by taking personal command of the army and promoting officers loyal to him. His reign witnessed
the decades-long campaign against Bulgaria, which ended in total Byzantine victory at the
Battle of Kleidion in 1014. Diplomatic efforts, critical for this success, also contributed to the
annexation of several Georgian provinces in the 1020s and coexistence with the new
Fatimid Caliphate. When he died in 1025, Basil's empire stretched from the Danube and Sicily in the west to the
Euphrates in the east; his swift expansion was unaccompanied by administrative reforms. (1031) by the Byzantines under
George Maniakes and the counterattack by the
Seljuk Turks|alt=Depiction of an army attacking a walled town After Constantine VIII's death in 1028, his daughters, the empresses
Zoe () and
Theodora (), held the keys to power: four emperors (
Romanos III,
Michael IV,
Michael V, and
Constantine IX) ruled only because of their connection to Zoe, while
Michael VI () was selected by Theodora. This political instability, regular budget deficits, a series of expensive military failures, and other problems connected to over-extension led to substantial issues in the empire; its strategic focus moved from maintaining its hegemony to prioritising defence. The empire soon came under sustained assault on three fronts, from the
Seljuk Turks in the east, the
Pecheneg nomads in the north, and the
Normans in the west. The Byzantine army struggled to confront these enemies, who did not organise themselves as traditional states, and were thus untroubled by defeats in set-piece battles. In 1071
Bari, the last remaining Byzantine settlement in Italy, was
captured by the Normans, while the Seljuks won a decisive victory at the
Battle of Manzikert, taking the emperor
Romanos IV Diogenes prisoner. The latter event sparked a decade-long civil war, and as a result the Seljuks took possession of Anatolia up to the
Sea of Marmara.
1081–1204: Komnenos and Angelos dynasties One prominent general,
Alexios I, usurped the throne in 1081. In contrast to the prior turmoil, the three reigns of Alexios (), his son
John II (), and his grandson
Manuel I () lasted a century and
restored the empire's regional authority for the final time. Alexios immediately faced the Normans under
Robert Guiscard and
repelled them through warfare and diplomacy. He then targeted the Pechenegs and
decisively defeated them in 1091 with help from the
Cumans, who were in turn defeated three years later. Finally, looking to recover Asia Minor from the Seljuks, he approached
Pope Urban II for help . He did not anticipate the scale of western Christendom's response—the
First Crusade led to the recapture of western Anatolia, although Alexios and its leaders soon fell out. The rest of his reign was spent
dealing with the Normans and Seljuks, establishing a new, loyal aristocracy to ensure stability, and carrying out fiscal and ecclesiastical reforms. from the
Hagia Sophia of Constantinople (modern Istanbul), depicting
Mary and
Jesus, flanked by
John II Komnenos (left) and his wife
Irene of Hungary (right), 12th century|alt=A mosaic depicting a haloed woman holding a baby, flanked by a man and woman, both crowned and haloed Alexios' concentration of power in the hands of his
Komnenos dynasty meant the most serious political threats came from within the imperial family—before his coronation, John II had to overcome
his mother Irene and
his sister Anna, and the primary threat during his reign was
his brother Isaac. John campaigned annually and extensively—he fought the Pechenegs in 1122, the
Hungarians in the late 1120s, and the Seljuks throughout his reign, waging
large campaigns in Syria in his final years—but he did not achieve large territorial gains. In 1138, John raised the imperial standard over the Crusader
Principality of Antioch to intimidate the city into allying with the Byzantines, but did not attack, fearing that it would provoke western Christendom to respond. Manuel I used his father's overflowing imperial treasury in pursuit of his ambitions, and also to secure the empire's position in an increasingly multilateral geopolitical landscape. Through a combination of
diplomacy and bribery, he cultivated a ring of allies and clients around the empire: the Turks of the
Sultanate of Rum, the
Kingdom of Hungary, the
Cilician Armenians, Balkan princes, Italian and Dalmatian cities, and most importantly Antioch and the
Crusader States, marrying
one of their princesses in 1161. Manuel averted the threat of war during the tumultuous passage of the
Second Crusade through Byzantine territories in 1147, but the campaign's failure was blamed on the Byzantines by western contemporaries. He was less successful militarily: an invasion of
Sicily was decisively defeated by
King William I in 1156, leading to tensions with
Frederick Barbarossa, the Holy Roman Emperor; two decades later, an invasion of Anatolia was resoundingly defeated at the
Battle of Myriokephalon. , by
Eugène Delacroix (1840)|alt=A painting of an army marching into a city gate with much smoke in the background Manuel's death left the empire rudderless and it soon came under intense pressure. His son
Alexios II was too young to rule, and his troubled regency was overthrown by his uncle
Andronikos I Komnenos: he was replaced by
Isaac II in 1185. Centrifugal forces swirled at the borders as ambitious rulers seized their chance: Hungary and the Turks captured Byzantine territories,
an exiled Komnenian prince seized Cyprus; and most injuriously,
a revolt in 1185 caused the foundation of a
resurrected Bulgarian state. Relations with the West deteriorated further after Constantinople allied with
Saladin, the vanquisher of the
Third Crusade, whose leaders also fought against Byzantium as they passed through its territory. In 1195, Isaac II was deposed by his brother
Alexios III; this quarrel proved fatal. The
Fourth Crusade was originally intended to target
Egypt, but amid strategic difficulties, Isaac II's son
Alexios Angelos convinced the crusaders to restore his father to the throne in exchange for a huge tribute. They
attacked Constantinople in 1203, reinstating Isaac II and his son to the throne. The new rulers swiftly grew unpopular and were deposed by
Alexios V, an event used by the crusaders as a pretext to
sack the city in April 1204, ransacking the wealth it had accumulated over nine centuries.
1204–1453: Palaiologos dynasty , |alt=A map showing the competing states after the Fourth Crusade. Byzantine territories fragmented into competing political entities. The crusaders crowned
Baldwin I as the ruler of a new
Latin Empire in Constantinople; it soon suffered
a crushing defeat against the Bulgarians in 1205. It also failed to expand west or east, where three Greek successor states had formed: the
Empire of Nicaea and the
Empire of Trebizond in Asia Minor, and the
Despotate of Epirus on the Adriatic. The Venetians acquired many ports and islands, and the
Principality of Achaea emerged in southern Greece. Trebizond
lost the key port of
Sinope in 1214 and thereafter was unable to affect matters away from the southeastern Black Sea. For a time, it seemed that Epirus was the one most likely to reclaim Constantinople from the Latins, and its ruler
Theodore Doukas crowned himself emperor, but he suffered a critical defeat at the
Battle of Klokotnitsa in 1230, and Epirote power waned. Nicaea, ruled by the
Laskarid dynasty and composed of a mixture of Byzantine refugees and native Greeks, blocked the Latins and the Seljuks of Rum from expanding east and west respectively.
John III () was a very capable emperor. His
protectionist economic policies strongly encouraged Nicaean
self-sufficiency, and he made many diplomatic treaties, especially after
Mongol armies
ravaged Bulgaria and
defeated Rum between 1237 and 1243. This chaos was an opportunity for John, and he fought many successful campaigns against the states disrupted by the
Mongol invasions. Soon after his death,
his grandson was usurped by
Michael VIII, founder of the
Palaiologos dynasty, who
recaptured Constantinople in 1261. Michael desired to restore the empire's glory through a rebuilding programme in Constantinople, clever diplomatic alliances, and expansionist wars in Europe. He staved off the threatening
Charles I of Anjou first by recognising papal primacy and certain Catholic doctrines at the 1274
Second Council of Lyon, and then by aiding the
Sicilian Vespers against Charles in 1282. However, his religious concessions were despised by most of the populace, and were repudiated by his successor
Andronikos II (). He and his grandson
Andronikos III () led several campaigns to restore imperial influence, succeeding in Epirus and Thessaly. They also made several critical mistakes, including dismissing the fleet in 1285, hiring the mercenary
Catalan Company, who turned on the Byzantines, in the 1300s, and fighting each other between 1320 and 1328. A disastrous civil war between 1341 and 1354 caused long-term economic difficulties, while the
Ottoman Turks gradually expanded. in 1453, depicted in a 15th-century French miniature|alt=A painting of a siege of a city The diminished and weak Byzantine state only survived for another century through effective diplomacy and fortunately timed external events. The Ottomans gradually subjugated Anatolia and simultaneously expanded into Europe from 1354, taking
Philippopolis in 1363,
Adrianopolis in 1369, and
Thessalonica in 1387. Emperors were crowned and deposed at the whim of the Venetians, Genoese, and Ottomans. After
Manuel II () refused to pay homage to Sultan
Bayezid I in 1394,
Constantinople was besieged until the rampaging warlord
Timur decisively
defeated Bayezid in 1402, with the city perilously close to surrender. Manuel II oversaw two decades of peace while the
Ottomans convulsed in civil war. In 1421, his unsuccessful backing of the claimant
Mustafa Çelebi led to a
renewed Turkish assault. Although
John VIII () reconciled with the Catholic West at the
Council of Florence, his empire steadily diminished. In 1452, Sultan
Mehmed II resolved to capture Constantinople, and laid siege early the following year. On 29 May 1453,
the city was captured, the last emperor,
Constantine XI, died in battle, and the Byzantine Empire ended. == Structures of the state ==