Misplaced Pages

Latest revision as of 18:12, 21 January 2025

Byzantine Empire
330–1453
The empire in 555 under Justinian I, its greatest extent since the fall of the Western Roman Empire, with vassals in pink
Capital	Constantinople (modern-day Istanbul)
Common languages	Latin and Greek Regional languages
Religion	Christianity (official)
Demonym(s)	Byzantine Roman
Government	Autocracy
Notable emperors
• 306–337	Constantine I
• 379–395	Theodosius I
• 408–450	Theodosius II
• 527–565	Justinian I
• 610–641	Heraclius
• 717–741	Leo III
• 976–1025	Basil II
• 1081–1118	Alexios I
• 1143–1180	Manuel I
• 1261–1282	Michael VIII
• 1449–1453	Constantine XI
Historical era	Late antiquity to Late Middle Ages
Population
• 457	16,000,000
• 565	26,000,000
• 775	7,000,000
• 1025	12,000,000
• 1320	2,000,000
Currency	Solidus, denarius, and hyperpyron

The Byzantine Empire, also referred to as the Eastern Roman Empire, was the continuation of the Roman Empire centred in Constantinople during late antiquity and the Middle Ages. The eastern half of the Empire survived the conditions that caused the fall of the West in the 5th century AD, and continued to exist until the fall of Constantinople to the Ottoman Empire in 1453. During most of its existence, the empire remained the most powerful economic, cultural, and military force in the Mediterranean world. The term "Byzantine Empire" was only coined following the empire's demise; its citizens referred to the polity as the "Roman Empire" and to themselves as "Romans". Due to the imperial seat's move from Rome to Byzantium, the adoption of state Christianity, and the predominance of Greek instead of Latin, modern historians continue to make a distinction between the earlier Roman Empire and the later Byzantine Empire.

During the earlier Pax Romana period, the western parts of the empire became increasingly Latinised, while the eastern parts largely retained their preexisting Hellenistic culture. This created a dichotomy between the Greek East and Latin West. These cultural spheres continued to diverge after Constantine I (r. 324–337) moved the capital to Constantinople and legalised Christianity. Under Theodosius I (r. 379–395), Christianity became the state religion, and other religious practices were proscribed. Greek gradually replaced Latin for official use as Latin fell into disuse.

The empire experienced several cycles of decline and recovery throughout its history, reaching its greatest extent after the fall of the west during the reign of Justinian I (r. 527–565), who briefly reconquered much of Italy and the western Mediterranean coast. The appearance of plague and a devastating war with Persia exhausted the empire's resources; the early Muslim conquests that followed saw 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 subsequently stabilised under the Isaurian dynasty. The empire was able to expand once more under the Macedonian dynasty, experiencing a two-century-long renaissance. This growth came to an end in 1071 after the defeat by the Seljuk Turks at the Battle of Manzikert. 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 by Latin armies at the end of 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 of existence. Its remaining territories were progressively annexed by the Ottomans in perennial wars fought throughout the 14th and 15th centuries. The fall of Constantinople to the Ottomans in 1453 ultimately brought the empire to an end. Many refugees who had fled the city after its capture settled in Italy and throughout Europe, helping to ignite the Renaissance. The fall of Constantinople is sometimes used to mark the dividing line between the Middle Ages and the early modern period.

Nomenclature

The inhabitants of the empire, now generally termed Byzantines, thought of themselves as Romans (Romaioi). Their Islamic neighbours similarly called their empire the "land of the Romans" (Bilād al-Rūm), but the people of medieval Western Europe preferred to call them "Greeks" (Graeci), due to having a contested legacy to Roman identity and to associate negative connotations from ancient Latin literature. The adjective "Byzantine", which derived from Byzantion (Latinised as Byzantium), the name of the Greek settlement Constantinople was established on, was only used to describe the inhabitants of that city; it did not refer to the empire, which they called Romanía—"Romanland".

After the empire's fall, early modern scholars referred to the empire by many names, including the "Empire of Constantinople", the "Empire of the Greeks", the "Eastern Empire", the "Late Empire", the "Low Empire", and the "Roman Empire". The increasing use of "Byzantine" and "Byzantine Empire" likely started with the 15th-century historian Laonikos Chalkokondyles, whose works were widely propagated, notably 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; however, some modern historians believe that, as an originally prejudicial and inaccurate term, it should not be used.

History

As the historiographical periodizations of "Roman history", "late antiquity", and "Byzantine history" significantly overlap, there is no consensus on a "foundation date" for the Byzantine Empire, if there was one at all. 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 in c. 300 AD. Still others hold that these starting points are too early or too late, and instead begin c. 500. Geoffrey Greatrex believes that it is impossible to precisely date the foundation of the Byzantine Empire.

Early history (pre-518)

In a series of conflicts between the third and first centuries BC, the Roman Republic gradually established hegemony over the eastern Mediterranean, while its government ultimately transformed into the one-person rule of an emperor. The Roman Empire enjoyed a period of relative stability until the third century AD, when a combination of external threats and internal instabilities caused the Roman state to splinter as regional armies acclaimed their generals as "soldier-emperors". One of these, Diocletian (r. 284–305), seeing that the state was too big to be ruled by one man, attempted to fix the problem by instituting a Tetrarchy, or rule of four, and dividing the empire into eastern and western halves. Although the Tetrarchy system quickly failed, the division of the empire proved an enduring concept.

Diocletian's reforms significantly altered governmental structure, reach and taxation, and these reforms also had the effect of downgrading the first capital, Rome. Constantine I (r. 306–337) secured sole power in 324. Over the following six years, he rebuilt the city of Byzantium as a capital city, which was renamed Constantinople. Rome was further from the important 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 who, having been granted citizenship, considered themselves "Roman". Constantine extensively reformed the empire's military and civil administration and instituted the gold solidus as a stable currency. He favoured Christianity, which he had converted to in 312.

Constantine's dynasty fought a lengthy conflict against Sasanid Persia and ended in 363 after the death of his son-in-law Julian. The short Valentinianic dynasty, occupied with wars against barbarians, religious debates, and anti-corruption campaigns, ended in the East after the death of Valens at the Battle of Adrianople in 378.

Valens's successor, Theodosius I (r. 379–395), restored political stability 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 Christianity over Arianism, 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 by a succession of "soldier-emperors", unlike the East, where administrators continued to hold power. Theodosius II (r. 408–450) largely left the rule of the east to officials such as Anthemius, who constructed the Theodosian Walls to defend Constantinople, now firmly entrenched as Rome's capital.

Theodosius' reign was marked by the theological dispute over Nestorianism, which was eventually deemed heretical, and by the formulation of the Codex Theodosianus law code. It also saw the arrival of Attila's Huns, who ravaged the Balkans and exacted a massive tribute from the empire; Attila however switched his attention to the rapidly-deteriorating western empire, and his people fractured after his death in 453. After Leo I (r. 457–474) 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 the office of western emperor was formally abolished.

Through a combination of luck, cultural factors, and political decisions, the Eastern empire never suffered from rebellious barbarian vassals and was never ruled by barbarian warlords—the problems which ensured the downfall of the West. Zeno (r. 474–491) convinced the problematic Ostrogoth king Theodoric to take control of Italy from Odoacer, which he did; dying when the empire was at peace, Zeno was succeeded by Anastasius I (r. 491–518). Although his Monophysitism brought occasional issues, Anastasius was a capable administrator and instituted several successful financial reforms including the abolition of the chrysargyron tax. He was the first emperor, since Diocletian, who did not face any serious problems affecting his empire.

518–717

The reign of Justinian I was a watershed in Byzantine history. Following his accession in 527, the law-code was rewritten as the influential Corpus Juris Civilis and Justinian produced extensive legislation on provincial administration; he reasserted imperial control over religion and morality through purges of non-Christians and "deviants"; and having ruthlessly subdued the 532 Nika revolt he rebuilt much of Constantinople, including the original Hagia Sophia. Justinian took advantage of political instability in Italy to attempt the reconquest of lost western territories. The Vandal Kingdom in North Africa was subjugated in 534 by the general Belisarius, who then invaded Italy; the Ostrogothic Kingdom was destroyed in 554.

In the 540s, however, Justinian began to suffer reversals on multiple fronts. Taking advantage of Constantinople's preoccupation with the West, Khosrow I of the Sasanian Empire invaded Byzantine territory and sacked Antioch in 540. Meanwhile, the emperor's internal reforms and policies began to falter, not helped by a devastating plague that killed a large proportion of the population and severely weakened 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 Second Council of Constantinople failed to make a real difference. Justinian died in 565; his reign saw more success than that of any other Byzantine emperor, yet he left his empire under massive strain.

Financially and territorially overextended, Justin II (r. 565–578) was soon at war on many fronts. The Lombards, fearing the aggressive Avars, conquered much of northern Italy by 572. The Sasanian wars restarted that year, and continued until the emperor Maurice finally emerged victorious in 591; by that time, the Avars and Slavs had repeatedly invaded the Balkans, causing great instability. Maurice campaigned extensively in the region during the 590s, but although he managed to re-establish 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 soon executed, but the destructive civil war accelerated the empire's decline.

Under Khosrow II, the Sassanids occupied the Levant and Egypt and pushed into Asia Minor, while Byzantine control of Italy slipped and the Avars and Slavs ran riot in the Balkans. Although Heraclius repelled a siege of Constantinople in 626 and defeated the Sassanids in 627, this was a pyrrhic victory. The early Muslim 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 as well as territorially—the loss of the wealthy eastern provinces had deprived Constantinople of three-quarters of its revenue.

The next seventy-five years are poorly documented. Arab raids into Asia Minor began almost immediately, and the Byzantines resorted to holding fortified centres and avoiding battle at all costs; although it was invaded annually, Anatolia avoided permanent Arab occupation. The outbreak of the First Fitna in 656 gave Byzantium breathing space, which it used wisely: some order was restored in the Balkans by Constans II (r. 641–668), who began the administrative reorganisation known as the "theme system", in which troops were allocated to defend specific provinces. With the help of the recently rediscovered Greek fire, Constantine IV (r. 668–685) repelled the Arab efforts to capture Constantinople in the 670s, but suffered a reversal against the Bulgars, who soon established an empire in the northern Balkans. Nevertheless, he and Constans had done enough to secure the empire's position, especially as the Umayyad Caliphate was undergoing another civil war.

Justinian II sought to build on the stability secured by his father Constantine but was overthrown in 695 after attempting to exact too much from his subjects; over the next twenty-two years, six more rebellions followed in an era of political instability. The reconstituted caliphate sought to break Byzantium by taking Constantinople, but the newly crowned Leo III managed to repel the 717–718 siege, the first major setback of the Muslim conquests.

718–867

Leo and his son Constantine V (r. 741–775), 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 II, and 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. However, due to both emperors' support for the Byzantine Iconoclasm, which opposed the use of religious icons, 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 with the Roman papacy.

In 780, Empress Irene assumed power on behalf of her son Constantine VI. Although she was a capable administrator who temporarily resolved the iconoclasm controversy, the empire was destabilized by her feud with her son. The Bulgars and Abbasids meanwhile 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 (r. 829–842), who exploited economic growth to complete construction programs, 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. However, Michael was posthumously vilified by historians loyal to the dynasty of his successor Basil I, who assassinated him in 867 and who was given credit for his predecessor's achievements.

867–1081

Basil I (r. 867–886) continued Michael's policies. His armies campaigned with mixed results in Italy but defeated the Paulicians of Tephrike. His successor Leo VI (r. 886–912) compiled and propagated a huge number of written works. These included the Basilika, a Greek translation of Justinian I's law-code which included over 100 new laws created by Leo; the Tactica, a military treatise; and the Book of the Eparch, which codified Constantinople's trading regulations. In non-literary contexts Leo was less successful: the empire lost in Sicily and against the Bulgarians, while he provoked theological scandal by marrying four times in an attempt to father a legitimate heir.

The early reign of that 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, which brought peace with Bulgaria and successes in the east under the general John Kourkouas, was ended in 944 by the machinations of his sons, whom Constantine soon usurped in turn. Constantine's ineffectual sole rule has often been construed as the zenith of Byzantine learning, but while several works were compiled, they were largely intended to legitimise and glorify the emperor's Macedonian dynasty. His son and successor died young; under two soldier-emperors, Nikephoros II (r. 963–969) and John I Tzimiskes (r. 969–976), the Roman 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 with the former's death and the latter's submission, and with a power struggle against the eunuch Basileios, who was dismissed in 985. Basil, who for unknown reasons 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 was preoccupied with the decades-long campaign against Bulgaria, which ended in total Byzantine victory at the Battle of Kleidion in 1018. Diplomatic efforts, critical for that 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, however, unaccompanied by administrative reforms.

After Constantine VIII's death in 1028, his daughters, the empresses Zoe (r. 1028–1052) and Theodora (r. 1042–1056), 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 (r. 1056–1057) was selected by Theodora. This political instability, regular budget deficits, a string 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 prioritizing 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 with confronting these enemies, who did not organise themselves as traditional states and were thus untroubled by defeats in set-piece battles. The year 1071 brought two consequential reverses: 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, during which the Seljuks took possession of Anatolia up to the Sea of Marmara.

1081–1204

One prominent general, Alexios I, usurped the throne in 1081. In contrast to the prior turmoil, the three reigns of Alexios (r. 1081–1118), his son John II (r. 1118–1143), and his grandson Manuel I (r. 1143–1180) lasted a century and restored the empire's regional authority for the final time. Alexios immediately faced the Normans under Robert Guiscard, who were repelled through warfare and diplomacy. He then targeted the Pechenegs, who were decisively defeated 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 c. 1095. He did not anticipate the scale of western Christendom's response—the First Crusade led to the recapture of western Anatolia, although Alexios soon fell out with its leaders. 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.

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, notably waging large campaigns in Syria in his final years—but 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 chose not to attack, fearing that it would provoke western Christendom to respond.

Manuel I utilised his father's overflowing imperial treasury in pursuit of his ambitions and 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.

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 soon overthrown by an uncle, who was himself 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 conflicted with Byzantium as they passed through its territory. In 1195, Isaac II was deposed by his brother Alexios III; this particular 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 grew swiftly unpopular and were deposed by Alexios V, which the crusaders used as a pretext to sack the city in April 1204, ransacking the wealth it had accumulated over nine centuries.

1204–1453

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 like 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 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 (r. 1221–1254) was a very capable emperor. His protectionist economic policies strongly encouraged Nicaean self-sufficiency, while 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, who fought numerous successful campaigns against the states which bore the brunt of 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 chose to expand the empire, gaining only short-term success. To avoid another sacking of the capital by the Latins, he forced the Church to submit to Rome, again a temporary solution for which the peasantry hated Michael and Constantinople. The efforts of Andronikos II and later his grandson Andronikos III marked Byzantium's last genuine attempts to restore the glory of the empire. However, the use of mercenaries by Andronikos II often backfired, like the time the Catalan Company ravaged the countryside, which increased public resentment towards Constantinople.

The situation became worse for Byzantium during the civil wars which erupted after Andronikos III died. A six-year-long civil war devastated the empire, allowing the Serbian ruler Stefan Dušan to overrun most of the empire's remaining territory and establish a Serbian Empire. In 1354, an earthquake at Gallipoli devastated the fort, allowing the Ottomans to conquer it and establish themselves in Europe, after originally being hired as mercenaries during the civil war by John VI Kantakouzenos. By the time the Byzantine civil wars ended, the Ottomans had defeated the Serbians and subjugated them as vassals. After the Battle of Kosovo, much of the Balkans became dominated by the Ottomans.

Constantinople at this stage was underpopulated and dilapidated. The population of the city had collapsed so severely that it was now little more than a cluster of villages separated by fields. On 2 April 1453, Sultan Mehmed's army of 80,000 men and large numbers of irregulars laid siege to the city. Despite a desperate last-ditch defence of the city by the massively outnumbered Christian forces (c. 7,000 men, 2,000 of whom were foreign), Constantinople finally fell to the Ottomans after a two-month siege on 29 May 1453. The final Byzantine emperor, Constantine XI Palaiologos, was last seen casting off his imperial regalia and throwing himself into hand-to-hand combat after the walls of the city were taken.

Government

Governance

The patriarch inaugurated emperors from 457 onwards, while the crowds of Constantinople proclaimed their support, thus legitimizing their rule. The senate originally had its own identity but later became a ceremonial extension of the emperor's court. The reign of Phocas (r. 602–610) was the first military coup after the third century, and he was one of 43 emperors violently removed from power. From Heraclius' accession in 610 till 1453, a total of nine dynasties ruled the Empire. During this time, for only 30 of the 843 years were the reigning emperors unrelated by blood or kinship, largely due to the practice of co-emperorship.

Diocletian and Constantine's reforms reorganized the Empire into Praetorian prefectures and separated the army from the civil administration. From the 7th century onward, these prefectures were reorganized into provinces and later divided into districts called themata, governed by military commanders known as strategos, who oversaw both civil and military matters. Before this change, cities were self-governing communities represented by central government and church officials, while emperors focused on defense and foreign relations. However, constant wars and raids by Arab forces drastically changed this structure. City councils declined, as did the local elites who supported them. Through his legal reforms, Leo VI (r. 886–912) centralised power, formally ending city councils' rights and the legislative authority of the senate.

Diplomacy

Diplomacy is often regarded as one of the Empire's lasting contributions to European history, particularly in preserving civilization in Eastern Europe. This reputation stems from its aggressive treaty negotiations, alliances with the enemies of its adversaries, and strategic partnerships. For instance, the Empire supported the Turks against the Persians during the Perso-Turkic War (627–629) and exploited tensions between the Umayyads in Spain and the Aghlabids in Sicily. Diplomacy frequently involved long-term embassies, hosting foreign royals as political pawns, and deliberately displaying wealth and power to ensure such impressions spread widely. Other diplomatic strategies included political marriages, granting titles, bribery, persuasion, and intelligence gathering. Notably, the 'Bureau of Barbarians', established in the 4th century, is considered one of the earliest foreign intelligence agencies.

Diplomacy after the reign of Theodosius I (r. 379–395) shifted significantly from the more conquest-focused policies of the Roman Republic, instead emphasizing peace as a strategic necessity. Even in the 6th century, when the Empire had greater resources and fewer threats, the enormous costs of defense, agricultural self-reliance, and aggressive neighbors made avoiding war a priority. Between the 4th and 8th centuries, diplomats capitalized on the Empire's reputation as the Orbis Romanus and its administrative sophistication to influence new settlements on former Roman territories. Byzantine diplomacy often drew fledgling states into dependency, creating a network of inter-state relations (the oikouménē) dominated by the Empire and leveraging Christianity to strengthen these ties. This network emphasized treaty-making, integrating new rulers into the "family of kings," and assimilating values, institutions, and attitudes. These practices have even been referred to as creating a "Byzantine Caliphate", where religion re-framed the civilised-versus-barbarian dichotomy in classical times. By contrast, diplomatic relations with Muslim states focused primarily on war-related issues, such as negotiating hostages or preventing hostilities.

Peace and survival, rather than conquest, were central objectives. Historians describe this approach as "defensive imperialism," which evolved between the 9th and 10th centuries to include halting and reversing Muslim advances, cultivating alliances with Armenians and Rus, and subjugating the Bulgarians. Diplomatic relations with Western states became more challenging after 752–753 and particularly during the Crusades, as shifts in the balance of power undermined the Empire's dominance and its use of the Limitrophe system. By the 11th century, the Empire adopted a principle of diplomatic equality, leveraging the emperor's personal presence to negotiate.

After recovering Constantinople in 1261, the Empire maintained its influence as a great power in the 13th and 14th centuries, despite its declining strength. This success is attributed to its efficient statecraft and strategic use of the Constantinople patriarch.

Law

Roman law originated with the Twelve Tables and evolved primarily through the annual Praetorian Edict and the opinions of educated specialists known as Jurists. Hadrian (r. 117–138) made the Praetorian Edict permanent and established a rule where a legal point jurists unanimously agreed on became law. Over time, conflicting legal sources caused confusion about what the law should be. Efforts to address this included two private collections of imperial constitutions compiled during Diocletian's reign (284–305), the Gregorianus and the Hermogenianus (r. 284–305).

Theodosius II (r. 402–450) formalized Roman law by appointing five jurists as principal authorities and compiling legislation issued since Constantine’s reign into the Codex Theodosianus. This process culminated in the Corpus Juris Civilis under Justinian I (r. 527–565), who commissioned a complete standardization of imperial decrees since Hadrian’s time and resolved conflicting legal opinions. The result became the definitive legal authority. This body of law covered not only civil matters but also public law, including imperial power and administrative organization. After 534, Justinian issued the Novellae (New Laws) in Greek, which marked a transition from Roman to Byzantine law. Legal historian Bernard Stolte distinguishes Roman law as this because Western Europe inherited law through the Latin texts of the Corpus Juris Civilis only.

Zachary Chitwood argues that the Corpus Juris Civilis was largely inaccessible in Latin, particularly in the provinces. Following the 7th-century Islamic conquests, people began questioning the development and application of law, leading to stronger ties between law and Christianity. This context influenced Leo III (r. 717–741) to develop the Ecloga, which emphasized humanity. The Ecloga inspired practical legal texts like the Farmers' Law, Seamen's Law, and Soldiers' Law, which Chitwood suggests were used daily in the provinces as companions to the Corpus Juris Civilis. During the Macedonian dynasty, efforts to reform law began with the Procheiron and the Eisagoge, which aimed to replace the Ecloga due to its association with iconoclasm and to define the emperor's power under prevailing laws. Leo VI (r. 886–912) completed a complete codification of Roman law in Greek through the Basilika, a monumental work of 60 books that became the foundation of Byzantine law. Later, in 1345, Constantine Harmenopoulos compiled the Hexabiblos, a six-volume law book derived from various Byzantine legal sources.

Military

Army

In the 5th century the East was fielding five armies of ~20,000 each in two army branches: stationary frontier units (limitanei) and mobile forces (comitatenses). The historian Anthony Kaldellis claims that the fiscally stretched Empire could only handle one major enemy at a time in the 6th century. The Islamic conquests between 634 and 642 led to significant changes, transforming the 4th-7th centuries field forces into provincial militia-like units which had a core of professional soldiers. The state shifted the burden of supporting the armies onto local populations and during Leo VI (r. 886–912) wove them into the tax system, where provinces evolved into military regions known as themata. Despite many challenges, the historian Warren Treadgold states that the field forces of the Eastern Empire between 284 and 602 were the best in the western world, while the historian Anthony Kaldellis believes that during the conquest period of the Macedonian dynasty (r. 867–1056), they were the best in the empire's history.

The military structure diversified to incorporate militia-like soldiers tied to regions, professional thematic forces (tourmai), and imperial units mostly based in Constantinople (tagmata). Foreign mercenaries also increasingly became employed, including the better-known tagma regiment, the Varangians, that guarded the emperor. The defence-orientated thematic militias were gradually replaced by more specialised offensive field armies, which could also counter the generals who rebelled against the emperor. When the Empire was expanding, the state began to commute thematic military service for cash payments: in the 10th century, there were 6,000 Varangians, another 3,000 foreign mercenaries and when including paid and unpaid citizen soldiers, the army on paper was 140,000 (an expeditionary force was 15,000 soldiers and field armies seldom were more than 40,000).

The thematic forces faded into insignificance—the government relying on the tagmata, mercenaries and allies instead—and which led to a neglect in defensive capability. Mercenary armies further fueled political divisions and civil wars that led to a collapse in the Empire's defence, and resulted in significant losses over territories such as Italy and the Anatolian heartland in the 11th century. Major military and fiscal reforms under the emperors of the Komnenian dynasty after 1081 re-established a modest-sized, adequately compensated and competent army. However, the costs were not sustainable and the structural weaknesses of the Komnenian approach—namely, the reliance on fiscal exemptions called pronoia—unraveled after the end of the reign of Manuel I (r. 1143–1180).

Navy

The navy dominated the eastern Mediterranean and were active also on the Black Sea, the Sea of Marmara, and the Aegean. Imperial naval forces were restructured to challenge Arab naval dominance in the 7th century, and later ceded their own maritime dominance to the Venetians and Genoans in the 11th century. The navy's patrols, as well as the chains of watchtowers and fire signals that warned inhabitants of threats, created the coastal defense for the Empire and were the responsibility of three themes: Cibirriote, Aegean Sea, Samos and an imperial fleet that consisted of mercenaries like the Norsemen and Russians that later became Varangians.

A new type of war galley, the dromon, appeared early in the sixth century. A multi-purpose variant, the chelandia, appeared during the reign of Justinian II (r. 685–711) and could be used to transport cavalry. The galleys were oar-driven, designed for coastal navigation, and are estimated to be able to operate for up to four days at a time. They were equipped with apparatus to deliver Greek fire in the 670s, and when Basil I (r. 867–886) developed professional marines, this combination kept a check on Muslim raiding through piracy. The dromon was the most advanced galley on the Mediterranean, until the 10th century development of a dromon called a galeai, which superseded dromons after the development of a late 11th century Western (Southern Italian) variant.

Late era (1204–1453)

The rulers of the Empire of Nicaea that retook the capital and the Palaiologos that ruled until 1453, built on the Komnenian foundation initially with four types of military units—the Thelematarii (volunteer soldiers), Gasmouloi and the Southern Peloponnese Tzacones/Lakones (marines), and Proselontes/Prosalentai (oarsmen)—but similarly could not sustain funding a standing force, largely relying on mercenaries as soldiers and fiscal exemptions to pronoiars who provided a small force of mostly cavalry. The Fleet was disbanded in 1284 and attempts were made to build it back later but the Genoese sabotaged the effort. The historian John Haldon claims that over time, the distinction between field troops and garrison units eventually disappeared as resources were strained. The frequent civil wars further drained the Empire, now increasingly instigated by foreigners such as the Serbs and Turks to win concessions, and the emperors were dependent on mercenaries to keep control, all the while dealing with the impact of the Black Death. The strategy of employing mercenary Turks to fight civil wars was repeatedly used by emperors and always led to the same outcome: subordination to the Turks.

Society

Demography

As many as 27 million people lived in the Empire at its peak in 540, but fell to as low as 12 million by 800. Although plague and territorial losses to Arab Muslim invaders weakened the Empire, it eventually recovered and by the near end of the Macedonian dynasty in 1025, the population is estimated to have been as high as 18 million. A few decades after the recapture of Constantinople in 1282, the Empire's population was in the range of 3–5 million; by 1312, the number had dropped to 2 million. By the time the Ottoman Turks captured Constantinople, there were only 50,000 people in the city, which was one-tenth of its population in its prime.

Education

Education was voluntary and required financial means, so the most literate people were often those associated with the church. Primary education focused on teaching foundational subjects like reading, writing, and arithmetic whereas Secondary school focused on the trivium and quadrivium as their curriculum. The Imperial University of Constantinople was formed in 425, and refounded in 1046 as a centre for law.

Slavery