Byzantine period

The Byzantine Empire, also known as the Eastern Roman Empire, was the continuation of the Roman Empire centred on Constantinople during late antiquity and the Middle Ages. Having survived the events that caused the fall of the Western Roman Empire in the 5th centuryAD, it endured until the fall of Constantinople to the Ottoman Empire in 1453. The term 'Byzantine Empire' was coined only after its demise; its citizens used the term 'Roman Empire' and called themselves 'Romans'.

During the early centuries of the Roman Empire, the western provinces were Latinised, but the eastern parts kept their Hellenistic culture. Constantine I () legalised Christianity and moved the capital to Constantinople. Theodosius I () made Christianity the state religion and Greek gradually replaced Latin for official use. The empire adopted a defensive strategy and, throughout its remaining history, experienced recurring cycles of decline and recovery.

It reached its greatest extent under the reign of Justinian I (), who briefly reconquered much of Italy and the western Mediterranean coast. A plague began around 541, and a devastating war with Persia drained the empire's resources. The Arab conquests led to the loss of the empire's richest provinces—Egypt and Syria—to the Rashidun Caliphate. In 698, Africa was lost to the Umayyad Caliphate, but the empire stabilised under the Isaurian dynasty. It expanded once more under the Macedonian dynasty, experiencing a two-century-long renaissance. Thereafter, periods of civil war and Seljuk incursion resulted in the loss of most of Asia Minor. The empire recovered during the Komnenian restoration, and Constantinople remained the largest and wealthiest city in Europe until the 13th century.

The empire was largely dismantled in 1204, following the sack of Constantinople during the Fourth Crusade; its former territories were then divided into competing Greek rump states and Latin realms. Despite the eventual recovery of Constantinople in 1261, the reconstituted empire wielded only regional power during its final two centuries. Its remaining territories were progressively annexed by the Ottomans in a series of wars fought in the 14th and 15th centuries. The fall of Constantinople to the Ottomans in 1453 brought the empire to an end, but its history and legacy remain topics of debate to this day.

Nomenclature

The empire's inhabitants, now generally termed "Byzantines", regarded themselves as Romans (in Greek, or ). Similarly, their Islamic contemporaries called their empire the "land of the Romans" (). After 800 AD Western Europe called them "Greeks" (), as the Papacy and medieval German emperors regarded themselves as the true inheritors of Roman identity. The adjective "Byzantine", derived from ( in Latin), the name of the Greek settlement Constantinople was established on, was only used to describe the inhabitants of the city; it did not refer to the empire, called ( or "Romanland") by its citizens.

Following the empire's fall, early modern scholars referred to it by many names, including the "Eastern Empire", the "Low Empire", the "Late Empire", the "Empire of the Greeks", "Empire of Constantinople", and "Roman Empire". The increasing use of "Byzantine" and "Byzantine Empire" started with the 15th-century historian Laonikos Chalkokondyles, whose works were widely propagated by Hieronymus Wolf. "Byzantine" was used adjectivally alongside terms such as "Empire of the Greeks" until the 19th century. It is now the primary term, used to refer to all aspects of the empire; some modern historians believe it should not be used because it was originally a prejudicial and inaccurate term.

History

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

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 further from the prosperous eastern provinces and in a less strategically important location; it was not esteemed by the "soldier-emperors", who ruled from the frontiers, or by 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, killed his titular successor Julius Nepos in 480, and 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.

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 (627), 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 Arabic 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

Leo and his son Constantine V (), two of the most capable Byzantine emperors, withstood continued Arab attacks, civil unrest, and natural disasters, and reestablished the state as a major regional power. Leo's reign produced the '' Ecloga'', a new code of law to succeed that of Justinian I. He also continued to reform the theme system in order to lead offensive campaigns against the Muslims, culminating in a decisive victory in 740. Constantine overcame an early civil war against his brother-in-law Artabasdos, made peace with 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 Byzantine historians; 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 sensational 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.

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.

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