The Byzantine Empire^[1] and Eastern Roman Empire are conventional names used to describe the Roman Empire during the Middle Ages, centered on its capital of Constantinople.

It was referred to by its inhabitants and neighboring nations simply as the Roman Empire (in Greek , Basileia R?mai?n), Empire of the Romans or Romania (, R?mani?). Its emperors continued the unbroken succession of Roman Emperors, preserving Greco-Roman legal and cultural traditions.

To the Islamic world it was known primarily as (Rûm "Rome"). Due to the linguistic, cultural, and demographic dominance of medieval Greek,^[2] it was known to many of its western European contemporaries as Imperium Graecorum, the Empire of the Greeks (see also the etymology section).

The definition of this empire as a distinct entity in itself constitutes an implicit or explicit rejection of its emperors and people's claim to be Romans and succesors of the Roman Empire - a rejection based on the assumption that only an empire using Latin as its official language and based in Italy can be considered truly "Roman", and that geographical move into hellenistic territory and linguistic-cultural adoption of Greek constituted a transformation into an inherently different identity.

The Eastern Roman Empire's evolution into a different culture from the ancient Roman Empire can be seen as a process beginning when the Emperor Constantine transferred the capital from Nicomedia in Anatolia to Byzantium, which was renamed New Rome or Constantinople, on the Bosphorus.

By the 7th century, under the reign of Emperor Heraclius, whose reforms changed the nature of the Empire's military and recognized Greek as the official language, the Empire had taken on a distinct new character.

During its thousand-year existence the Empire suffered numerous setbacks and losses of territory but remained one of the most powerful economic, cultural and military forces in Europe. The empire's influence also spread into North Africa and the near East for much of the Middle Ages.

After a final recovery under the Komnenian dynasty in the 12th century the Empire slipped into a long decline culminating in the capture of Constantinople and the remaining territories by the Ottoman Turks in the 15th century.

The Empire, a bastion of Christianity and one of the prime trade centers in the world, helped to shield Western Europe from early Muslim expansion, provided a stable gold currency for the Mediterranean region, influenced the laws, political systems, and customs of much of Europe and the Middle East, and preserved much of the literary works and scientific knowledge of ancient Greece, Rome, and many other cultures.

Etymology

The term "Byzantine Empire" is an invention of historians and was never used during the Empire's lifetime. The Empire's name in Greek was Basileia Rh?mai?n () — "The Empire of the Romans" — a translation of the Latin name of the Roman Empire (); or just Rh?mania ().

The term "Byzantine" itself comes from "Byzantium", the name that the city of Constantinople had before it became the capital of Constantine. This older name of the city would rarely be used from this point onward except in historical or poetic contexts.

The designation of the Empire as "Byzantine" began in Western Europe in 1557, when German historian Hieronymus Wolf published his work Corpus Historiæ By­zantinæ, a collection of Byzantine sources. The publication in 1648 of the Byzantine du Louvre (Corpus Scriptorum Historiæ Byzantinæ), and in 1680 of Du Cange's Historia Byzantina further popularized the use of Byzantine among French authors, such as Montesquieu.^[3] It was not until the 19th century, however, with the birth of modern Greece, that the term "Byzantine" came into general use in the Western world.

Before this, the Empire was described by Western Europeans as Imperium Graecorum (Empire of the Greeks)—Byzantine claims to Roman inheritance had been actively contested from at least the time of the coronation of Charlemagne as Imperator Augustus by Pope Leo III in 800. Whenever the Popes or the rulers of the West wanted to make use of the name Roman to refer to the Byzantine emperors, they preferred the term Imperator Romaniæ instead of Imperator Romanorum, a title that Westerners maintained applied only to Charlemagne and his successors.^[4]

Origin

The Tetrarchy

Map of the Roman Empire ca. 395, showing the dioceses and praetorian prefectures of Gaul, Italy, Illyricum and Oriens (east), roughly analogous to the four Tetrarchs' zones of influence after Diocletian's reforms.

Diocletian was responsible for creating a new administrative system (the tetrarchy).^[6] He associated himself with a co-emperor, or Augustus. Each Augustus was then to adopt a young colleague, or Caesar, to share in the rule and eventually to succeed the senior partner. After the abdication of Diocletian and Maximian, however, the tetrachy collapsed, and Constantine I replaced it with the dynastic principle of hereditary succession.^[7]

Constantine I and his successors

The Baptism of Constantine painted by Raphael's pupils (1520–1524, fresco, Vatican City, Apostolic Palace). Eusebius of Caesaria records that, as was customary among Christian converts at the time, Constantine delayed receiving baptism until shortly before his death.^[8]

Constantine built upon the administrative reforms introduced by Diocletian.^[10] He stabilized the coinage (the gold solidus that he introduced became a highly prized and stable currency^[11]), and made changes to the structure of the army. To divide administrative responsibilities, Constantine replaced the single praetorian prefect, who had traditionally exercised both military and civil functions, with regional prefects enjoying civil authority alone. In the course of the 4th century, four great sections emerged from these Constantinian beginnings, and the practice of separating civil from military authority persisted until the 7th century.^[12]

Under Constantine, Christianity did not become the exclusive religion of the state, but enjoyed imperial preference, since the Emperor supported it with generous privileges: clerics were exempted from personal services and taxation, Christians were preferred for administrative posts, and bishops were entrusted with judicial responsibilities.^[13] Constantine established the principle that emperors should not settle questions of doctrine, but should summon general ecclesiastical councils for that purpose. The Synod of Arles was convened by Constantine, and the First Council of Nicaea showcased his claim to be head of the Church.^[14]

The state of the Empire in 395 may be described in terms of the outcome of Constantine's work. The dynastic principle was established so firmly that the emperor who died in that year, Theodosius I, could bequeath the imperial office jointly to his sons: Arcadius in the East and Honorius in the West. Theodosius was the last emperor to rule over the full extent of the empire in both its halves.^[15]

Early history

Leo I of the Byzantine Empire (401–474, reigned 457–474).

His successor, Marcian, refused to continue to pay this exorbitant sum. However, Attila had already diverted his attention to the Western Roman Empire.^[17] After he died in 453, his empire collapsed and Constantinople initiated a profitable relationship with the remaining Huns, who would eventually fight as mercenaries in Byzantine armies.^[18]

After the fall of Attila, the true chief in Constantinople was the Alan general Aspar. Leo I managed to free himself from the influence of the non-Orthodox chief by supporting the rise of the Isaurians, a semi-barbarian tribe living in southern Anatolia. Aspar and his son Ardabur were murdered in a riot in 471, and henceforth, Constantinople restored Orthodox leadership for centuries.^[19]

Leo was also the first emperor to receive the crown not from a military leader, as was the Roman tradition, but from the Patriarch of Constantinople, representing the ecclesiastical hierarchy. This change became permanent, and in the Middle Ages the religious characteristic of the coronation completely supplanted the old military form. In 468, Leo unsuccessfully attempted to reconquer North Africa from the Vandals.^[20] By that time, the Western Roman Empire was restricted to Italy and the lands south of the Danube as far as the Balkans (the Angles and Saxons had been invading and settling Britain since the early decades of the 5th century; the Visigoths and Suebi had possessed portions of Hispania since 417, and the Vandals had entered Africa in 429; Gaul was contested by the Franks under Clovis I, Burgundians, Bretons, Visigoths and some Roman remnants; and Theodoric was destined to rule in Italy until 526^[15]).

In 466, as a condition of his Isaurian alliance, Leo married his daughter Ariadne to the Isaurian Tarasicodissa, who took the name Zeno. When Leo died in 474, Zeno and Ariadne's younger son succeeded to the throne as Leo II, with Zeno as regent. When Leo II died later that year, Zeno became emperor. The end of the Western Empire is sometimes dated to 476, early in Zeno's reign, when the Germanic Roman general Odoacer deposed the titular Western Emperor Romulus Augustus, but declined to replace him with another puppet.

Eastern Roman Empire, c. AD 480

In 475, Zeno was deposed by Basiliscus, the general who led Leo I's 468 invasion of North Africa, but he recovered the throne twenty months later. However, he faced a new threat from another Isaurian, Leontius, who was also elected rival emperor. In 491 Anastasius I, an aged civil officer of Roman origin, became emperor, but it was not until 498 that the forces of the new emperor effectively took the measure of Isaurian resistance.^[15] Anastasius revealed himself to be an energetic reformer and an able administrator. He perfected Constantine I's coinage system by definitively setting the weight of the copper follis, the coin used in most everyday transactions.^[21] He also reformed the tax system, and permanently abolished the hated chrysargyron tax. The State Treasury contained the enormous sum of 145,150 kg (320,000 lbs) of gold when he died.

Justinian I and his successors

Justinian depicted on one of the famous mosaics of the Basilica of San Vitale, Ravenna.

Nevertheless, the Ostrogoths were soon reunited under the command of Totila and captured Rome on 17 December 546; Belisarius was eventually recalled by Justinian in early 549.^[25] The arrival of the Armenian eunuch Narses in Italy (late 551) with an army of some 35,000 men marked another shift in Gothic fortunes. Totila was defeated and died at the Battle of Busta Gallorum. His successor, Teias, was likewise defeated at the Battle of Mons Lactarius (October 552). Despite continuing resistance from a few Goth garrisons and two subsequent invasions by the Franks and Alamanni, the war for the Italian peninsula was at an end.^[26] In 551, a noble of Visigothic Hispania, Athanagild, sought Justinian's help in a rebellion against the king, and the emperor dispatched a force under Liberius, who, although elderly, proved himself a successful military commander. The Byzantine empire held on to a small slice of the Spania coast until the reign of Heraclius.^[27]

In the east, Roman-Persian Wars continued until 561 when Justinian's and Khusro's envoys agreed on a 50-year peace. By the mid-550s, Justinian had won victories in most theatres of operation, with the notable exception of the Balkans, which were subjected to repeated incursions from the Slavs. In 559, the Empire faced a great invasion of Kutrigurs and Sclaveni. Justinian called Belisarius out of retirement, but once the immediate danger was over, the emperor took charge himself. The news that Justinian was reinforcing his Danube fleet made the Kutrigurs anxious, and they agreed to a treaty which gave them a subsidy and safe passage back across the river.^[23]

Theodora (here with her retinue, mosaic from Basilica of San Vitale, Ravenna), Justinian's influential wife, was a former mime actress, whose earlier life is vividly described by Procopius in Secret History.^[28]

During the 6th century, the traditional Greco-Roman culture was still influential in the Eastern empire with prominent representatives such as the natural philosopher John Philoponus. Nevertheless, the Christian philosophy and culture were in the ascendant and began to dominate the older culture. Hymns written by Romanos the Melode marked the development of the Divine Liturgy, while architects and builders worked to complete the new Church of the Holy Wisdom, Hagia Sophia, designed to replace an older church destroyed in the course of the Nika revolt. Hagia Sophia stands today as one of the major monuments of architectural history.^[15] During the 6th and 7th centuries the Empire was struck by a series of epidemics, which would greatly devastate the population, contributing to a significant economic decline and weakening of the Empire.^[31]

Justinian's successor, Justin II, refused to pay the large tribute to the Persians. Meanwhile, the Germanic Lombards invaded Italy; by the end of the century only a third of Italy was in Byzantine hands. Justin's successor, Tiberius II, choosing between his enemies, awarded subsidies to the Avars while taking military action against the Persians. Although Tiberius' general, Maurice, led an effective campaign on the eastern frontier, subsidies failed to restrain the Avars. They captured the Balkan fortress of Sirmium in 582, while the Turks began to make inroads across the Danube. Maurice, who in the meantime had become emperor, made peace with the Sassanian Emperor Khosrau II, achieving access to Armenia, and forced the Avars and Slavs back across the Danube by 602.^[15]

Heraclian dynasty and shrinking borders

After Maurice's murder by Phocas, Khosrau used the pretext to reconquer the Roman province of Mesopotamia.^[32] Phocas, an unpopular ruler who is invariably described in Byzantine sources as a "tyrant", was the target of a number of senate-led plots. He was eventually deposed in 610 by Heraclius, who sailed to Constantinople from Carthage with an icon affixed to the prow of his ship.^[33] Following the accession of Heraclius the Sassanid advance pushed deep into Asia Minor, also occupying Damascus and Jerusalem and removing the True Cross to Ctesiphon.^[34] The counter-offensive of Heraclius took on the character of a holy war, and an acheiropoietos image of Christ was carried as a military standard.^[35] Similarly, when Constantinople was saved from an Avar siege in 626, the victory was attributed to the icons of the Virgin which were led in procession by Patriarch Sergius about the walls of the city.^[36] The main Sassanid force was destroyed at Nineveh in 627, and in 629 Heraclius restored the True Cross to Jerusalem in a majestic ceremony.^[37] The war had exhausted both the Byzantine and Sassanid Empire, and left them extremely vulnerable to the Arab forces which emerged in the following years.^[38] The Byzantines suffered a crushing defeat at the Battle of Yarmuk in 636, and Ctesiphon fell in 634.^[39]

Heraclius was the first emperor to replace the traditional Latin title for his office (Augustus) with the Greek Basileus ().^[40] This shift from Latin to Greek finds a parallel in the contemporary abandonment of Latin in official documents.^[41] In an attempt to heal the doctrinal divide between Chalcedonian and monophysite Christians, Heraclius proposed monotheletism as a compromise. In 638 the new doctrine was posted in the narthex of Hagia Sophia as part of a text called the Ekthesis, which also forbade further discussion of the issue. By this time, however, Syria and Palestine, both hotbeds of monophysite belief, had fallen to the Arabs, and another monophysite center, Egypt, fell by 642. Ambivalence toward Byzantine rule on the part of monophysites may have lessened local resistance to the Arab expansion.^[42]

Heraclius did succeed in establishing a dynasty, and his descendants held onto the throne, with some interruption, until 711. Their reigns were marked both by major external threats, from the west and the east, which reduced the territory of the empire to a fraction of its 6th-century extent, and by significant internal turmoil and cultural transformation.

Byzantine Empire by 650; by this year it lost all of its southern provinces except the Exarchate of Carthage.

The Greek fire was first used by the Byzantine Navy during the Byzantine-Arab Wars (from the Madrid Skylitzes, Biblioteca Nacional de España, Madrid).

The withdrawal of massive amounts of troops from the Balkans to combat the Persians and then the Arabs in the east opened the door for the gradual southward expansion of Slavic peoples into the peninsula, and, as in Anatolia, many cities shrank to small fortified settlements.^[46] In the 670s the Bulgars were pushed south of the Danube by the arrival of the Khazars, and in 680 Byzantine forces which had been sent to disperse these new settlements were defeated. In the next year Constantine IV signed a treaty with the Bulgar khan Asparukh, and the new Bulgarian state assumed sovereignty over a number of Slavic tribes which had previously, at least in name, recognized Byzantine rule.^[47] In 687–688, emperor Justinian II led an expedition against the Slavs and Bulgars which made significant gains, although the fact that he had to fight his way from Thrace to Macedonia demonstrates the degree to which Byzantine power in the north Balkans had declined.^[48]

The one Byzantine city that remained relatively unaffected, despite a significant drop in population and at least two outbreaks of the plague, was Constantinople.^[49] However, the imperial capital was marked by its own variety of conflict, both political and religious. Constans II continued the monothelete policy of his grandfather, Heraclius, meeting with significant opposition from laity and clergy alike. The most vocal opponents, Maximus the Confessor and Pope Martin I were arrested, brought to Constantinople, tried, tortured, and exiled.^[50] Constans seems to have become immensely unpopular in the capital, and moved his residence to Syracuse, Sicily, where he was ultimately murdered by a member of his court.^[51] The Senate experienced a revival in importance in the seventh century and clashed with the emperors on numerous occasions.^[52] The final Heraclian emperor, Justinian II, attempted to break the power of the urban aristocracy through severe taxation and the appointment of "outsiders" to administrative posts. He was driven from power in 695, and took shelter first with the Khazars and then with the Bulgars. In 705 he returned to Constantinople with the armies of the Bulgar khan Tervel, retook the throne, and instituted a reign of terror against his enemies. With his final overthrow in 711, supported once more by the urban aristocracy, the Heraclian dynasty came to an end.^[53]

The 7th century was a period of radical transformation. The empire which had once stretched from Spain to Jerusalem was now reduced to Anatolia, Chersonesos, and some fragments of Italy and the Balkans. The territorial losses were accompanied by a cultural shift; urban civilization was massively disrupted, classical literary genres were abandoned in favor of theological treatises,^[54] and a new "radically abstract" style emerged in the visual arts.^[55] That the empire survived this period at all is somewhat surprising, especially given the total collapse of the Sassanid Empire in the face of the Arab expansion, but a remarkably coherent military reorganization helped to withstand the exterior pressures and laid the groundwork for the gains of the following dynasty.^[56]

Isaurian dynasty and Iconoclasm

The Byzantine Empire at the accession of Leo III, c. 717. Striped land shows land raided by the Arabs. Click on the image for names of provinces

The 8th and 9th centuries were also dominated by controversy and religious division over Iconoclasm. Icons were banned by Leo and Constantine, leading to revolts by iconodules (supporters of icons) throughout the empire. After the efforts of Empress Irene, the Second Council of Nicaea met in 787, and affirmed that icons could be venerated but not worshipped. Irene is said to have endeavored to negotiate a marriage between herself and Charlemagne, but, according to Theophanes the Confessor, the scheme was frustrated by Aetios, one of her favourites.^[58] In 813 Leo V the Armenian restored the policy of iconoclasm, but in 843 Empress Theodora restored the veneration of the icons with the help of Patriarch Methodios.^[59] Iconoclasm played its part in the further alienation of East from West, which worsened during the so-called Photian Schism, when Pope Nicholas I challenged Photios' elevation to the patriarchate.

Macedonian dynasty and resurgence

Minature from the Paris Psalter, 10th century. Evidence of enduring artistic traditions reaching the Antiquity

Internal developments

Although traditionally attributed to Basil I (867?886), initiator of the Macedonian dynasty, the Macedonian Renaissance has been more recently ascribed to the reforms of his predecessor, Michael III (842?867) and his wife's counsellor, the erudite Theoktistos. The latter in particular favoured culture at the court, and, with a careful financial policy, steadily increased the gold reserves of the Empire. The rise of the Macedonian dynasty coincided with internal developments which strengthened the religious unity of the empire.^[61] The iconoclast movement was experiencing a steep decline: this favoured its soft suppression by the emperors and the reconciliation of the religious strife that had drained the imperial resources in the previous centuries. Despite occasional tactical defeats, the administrative, legislative, cultural and economic situation continued to improve under Basil's successors, especially with Romanos I Lekapenos (920?944). The theme system reached its definitive form in this period. The church establishment began to loyally support the imperial cause, and the power of the landowning class was limited in favour of agricultural small holders, who made up an important part of the military force of the Empire. These favourable conditions contributed to the increasing ability of the emperors to wage war against the Arabs.

Wars against the Muslims

Byzantine Empire, c. 867 AD

The process of reconquest began with variable fortunes. The temporary reconquest of Crete (843) was followed by a crushing Byzantine defeat on the Bosporus, while the emperors were unable to prevent the ongoing Muslim conquest of Sicily (827?902). Using present day Tunisia as their launching pad, the Muslims conquered Palermo in 831, Messina in 842, Enna in 859, Syracuse in 878, Catania in 900 and the final Byzantine stronghold, the fortress of Taormina, in 902.

These drawbacks were later counterbalanced by a victorious expedition against Damietta in Egypt (856), the defeat of the Emir of Melitene (863), the confirmation of the imperial authority over Dalmatia (867), and Basil I's offensives towards the Euphrates (870s). Unlike the deteriorating situation in Sicily, Basil I handled the situation in southern Italy well enough and the province would remain in Byzantine hands for the next 200 years.

The threat from the Muslims was meanwhile reduced by inner struggles and by the rise of the Turks in the east. Muslims received assistance however from the Paulician sect, which had found a large following in the eastern provinces of the Empire and, facing persecution under the Byzantines, often fought under the Arab flag. It took several campaigns to subdue the Paulicians, who were eventually defeated by Basil I.^[60]

In 904, disaster struck the empire when its second city, Thessaloniki, was sacked by an Arab fleet led by a Byzantine renegade. The Byzantine military responded by destroying an Arab fleet in 908, and sacking the city of Laodicea in Syria two years later. Despite this revenge, the Byzantines were still unable to strike a decisive blow against the Muslims, who inflicted a crushing defeat on the imperial forces when they attempted to regain Crete in 911.

The situation on the border with the Arab territories remained fluid, with the Byzantines alternatively on the offensive or defensive. The Varangians, who attacked Constantinople for the first time in 860, constituted another new challenge. In 941 they appeared on the Asian shore of the Bosporus, but this time they were crushed, showing the improvements in the Byzantine military position after 907, when only diplomacy had been able to push back the invaders. The vanquisher of the Varangians was the famous general John Kourkouas, who continued the offensive with other noteworthy victories in Mesopotamia (943): these culminated in the reconquest of Edessa (944), which was especially celebrated for the return to Constantinople of the venerated Mandylion.

The soldier emperors Nikephoros II Phokas (reigned 963?969) and John I Tzimiskes (969?976) expanded the empire well into Syria, defeating the emirs of north-west Iraq and reconquering Crete and Cyprus. At one point under John, the empire's armies even threatened Jerusalem, far to the south. The emirate of Aleppo and its neighbours became vassals of the empire in the east, where the greatest threat to the empire was the Egyptian Fatimid kingdom.^[60] After much campaigning, the last Arab threat to Byzantium was defeated when Basil II rapidly drew 40,000 mounted soldiers to relieve Roman Syria. With a surplus of resources and victories thanks to the Bulgar and Syrian campaigns, Basil II planned an expedition against Sicily to re-take it from the Arabs there. After his death in 1025, the expedition set off in the 1040s and was met with initial, but stunted success.

Wars against the Bulgarians

Emperor Basil II the Bulgar Slayer (976?1025).

The traditional struggle with the See of Rome continued, spurred by the question of religious supremacy over the newly Christianized Bulgaria. This prompted an invasion by the powerful Tsar Simeon I in 894, but this was pushed back by the Byzantine diplomacy, which called on the help of the Hungarians. The Byzantines were in turn defeated, however, at the Battle of Bulgarophygon (896), and obliged to pay annual subsides to the Bulgarians. Later (912) Simeon even had the Byzantines grant him the crown of basileus of Bulgaria and had the young emperor Constantine VII marry one of his daughters. When a revolt in Constantinople halted his dynastic project, he again invaded Thrace and conquered Adrianople.^[60]

A great imperial expedition under Leo Phocas and Romanos Lekapenos ended again with a crushing Byzantine defeat at the Battle of Anchialus (917), and the following year the Bulgarians were free to ravage northern Greece up to Corinth. Adrianople was captured again in 923 and in 924 a Bulgarian army laid siege to Constantinople. The situation in the Balkans improved only after Simeon's death in 927.

The Empire under Basil II

Relations with Kiev Rus

Rus under the walls Constantinople (860)

Prince Oleg leads a squadron of horse-driven boats to the walls of Tsargrad. A medieval Kiev Rus illumination (907)

Between 800 and 1100 the Empire developed a mixed relationship with the new state of Kiev Rus that emerged to the north across the Black Sea.

Byzantine Empire quickly became a main trading and cultural partner for Kiev. After christianizing Rus Vladimir the Great empolyed many architects and artists to work on numerous cathedrals and churches around Rus, expanding the Byzantine influence even further.

Kiev Princes were often married into the Byzantine imperial family and Constantinople often employed Princes' armies, most notably Vladimir the Great presented Byzantine with the famous Varangian Guard - an army of vicious Scandinavian mercenaries. Some believe that it was done in exchange for the marriage to Basil's sister Anna to Vladimir.^[60] However, as Primary Chronicle states the marriage was in exchange for the Rus conversion to Orthodoxy, the Varangian Guard (although a signifficant one) was a by-product of this exchange.

These relationships were not always friendly. During those three hundred years Constantinople and other Byzantine cities were sacked several times by the armies of Kiev Rus (see Rus'-Byzantine Wars). Kiev never went far enough to actually endanger the Empire, those wars were only a tool to force the Byzantine to sign increasingly favorable trade treaties, the texts of which are recorded in the Primary Chronicle (Rus'-Byzantine Treaty (907))^[63] and other historical documents. Constantinople at the same time constantly played Kiev Rus, Bulgaria, and Poland against each other.

The Byzantine influence on Kiev Rus cannot be underestimated. Byzantine-style writing became a standard for the Cyrillic alphabet, Byzantine architecture was dominating in Kiev, and as a main trading partner Byzantine played a critical role in the establishment, rise and fall of Kiev Rus.

The climax

The Byzantine Empire and its themata in 1045. At this point, the Empire was the most powerful state in the Mediterranean.

The Byzantine Empire then stretched to Armenia in the east, to Calabria in Southern Italy in the west.^[60] Many successes had been achieved, ranging from the conquest of Bulgaria, to the annexation of parts of Georgia and Armenia, to the total annihilation of an invading force of Egyptians outside Antioch. Yet even these victories were not enough; Basil considered the continued Arab occupation of Sicily to be an outrage. Accordingly, he planned to reconquer the island, which had belonged to the empire for over 300 years (c. 550 ? c. 900). However, his death in 1025 put an end to the project.^[60]

The 11th century was also momentous for its religious events. In 1054, relations between Greek-speaking Eastern and Latin-speaking Western traditions within the Christian Church reached a terminal crisis. Although there was a formal declaration of institutional separation, on 16 July, when three papal legates entered the Hagia Sophia during Divine Liturgy on a Saturday afternoon and placed a bull of excommunication on the altar, the so-called Great Schism was actually the culmination of centuries of gradual separation. Although the schism was brought about by doctrinal disputes (in particular, Eastern refusal to accept the Western Church doctrine of the filioque, or double procession of the Holy Spirit), disputes over administration and political issues had simmered for centuries. The formal separation of the Byzantine Orthodox Church and the Western Catholic Church would have wide ranging consequences for the future of Byzantium.

Crisis and fragmentation

Diptych of Romanos and Eudocia Macrembolitissa crowned by Christ (Bibliothèque nationale de France, Paris).

Map of Italy on the eve of the arrival of the Normans

It was in Asia Minor, however, that the greatest disaster would take place. The Seljuq Turks made their first explorations across the Byzantine frontier into Armenia in 1065 and in 1067. The emergency lent weight to the military aristocracy in Anatolia who, in 1068, secured the election of one of their own, Romanos Diogenes, as emperor. In the summer of 1071, Romanos undertook a massive eastern campaign to draw the Seljuks into a general engagement with the Byzantine army. At Manzikert Romanos not only suffered a surprise defeat at the hands of Sultan Alp Arslan, but was also captured. Alp Arslan treated him with respect, and imposed no harsh terms on the Byzantines.^[65] In Constantinople, however, a coup took place in favor of Michael Doukas, who soon faced the opposition of Nikephoros Bryennios and Nikephoros Botaneiates. By 1081 the Seljuks expanded their rule over virtually the entire Anatolian plateau from Armenia in the east to Bithynia in the west and founded their capital in Nicea.^[67]

Komnenian dynasty and the crusaders

Alexios I and the First Crusade

The Byzantine Empire and the Sultanate of Rum before the Crusades

Having achieved stability in the West, Alexios could turn his attention to the severe economic difficulties and the disintegration of the empire's traditional defences.^[69] However, he still did not have enough manpower to recover the lost territories in Asia Minor, and to advance against the Seljuks. At the Council of Piacenza in 1095, Alexios' envoys spoke to Pope Urban II about the suffering of the Christians of the East, and underscored that without help from the West they would continue to suffer under Muslim rule. Urban saw Alexius' request as a dual opportunity to cement Western Europe and enhance papal power.^[70] On 27 November 1095, Pope Urban II called together the Council of Clermont, and urged all those present to take up arms under the sign of the Cross and launch an armed pilgrimage to recover Jerusalem and the East from the Muslims. The response in Western Europe was overwhelming.^[15]

The very brief first coinage of the Thessaloniki mint, which Alexios opened as he passed through in September 1081 on his way to confront the invading Normans under Robert Guiscard.

Alexios had anticipated help in the form of mercenary forces from the West, but was totally unprepared for the immense and undisciplined force which soon arrived in Byzantine territory. It was no comfort to Alexius to learn that four of the eight leaders of the main body of the Crusade were Normans, among them Bohemund. Since the crusade had to pass through Constantinople, however, the Emperor had some control over it. He required its leaders to swear to restore to the empire any towns or territories they might conquer from the Turks on their way to the Holy Land. In return, he gave them guides and a military escort.^[71] Alexios was able to recover a number of important cities and islands, and in fact much of western Asia Minor. Nevertheless, the crusaders believed their oaths were invalidated when Alexios did not help them during the siege of Antioch (he had in fact set out on the road to Antioch, but had been persuaded to turn back by Stephen of Blois, who assured him that all was lost and that the expedition had already failed).^[72] Bohemund, who had set himself up as Prince of Antioch, briefly went to war with the Byzantines, but agreed to become Alexios' vassal under the Treaty of Devol in 1108, which marked the end of Norman threat during Alexios' reign.^[73]

Medieval manuscript depicting the Capture of Jerusalem during the First Crusade.

John II, Manuel I and the Second Crusade

John II Komnenos left the imperial treasury full, and did not call for the execution or maiming of a single subject during his reign. Nicknamed 'John the Good', he is regarded by the Byzantine historian Niketas Choniates as the best emperor of the Komnenian dynasty.^[75]

Alexios' son John II Komnenos succeeded him in 1118, and was to rule until 1143. John was a pious and dedicated emperor who was determined to undo the damage his empire had suffered at the battle of Manzikert, half a century earlier.^[76] Famed for his piety and his remarkably mild and just reign, John was an exceptional example of a moral ruler, at a time when cruelty was the norm.^[77] For this reason, he has been called the Byzantine Marcus Aurelius. In the course of his twenty-five year reign, John made alliances with the Holy Roman Empire in the west, decisively defeated the Pechenegs at the Battle of Beroia,^[78] and personally led numerous campaigns against the Turks in Asia Minor. John's campaigns fundamentally changed the balance of power in the east, forcing the Turks onto the defensive and restoring to the Byzantines many towns, fortresses and cities right across the peninsula.^[75] He also thwarted Hungarian, and Serbian threats during the 1120s, and in 1130 allied himself with the German emperor Lothair III against the Norman King Roger II of Sicily.^[79] In the later part of his reign John focused his activities on the East. He defeated the Danishmend emirate of Melitene, and reconquered all of Cilicia, while forcing Raymond of Poitiers, Prince of Antioch, to recognize Byzantine suzerainty. In an effort to demonstrate the Byzantine emperor's role as the leader of the Christian world, John marched into the Holy Land at the head of the combined forces of Byzantium and the Crusader states; yet despite the great vigour with which he pressed the campaign, John's hopes were disappointed by the treachery of his Crusader allies.^[80] In 1142 John returned to press his claims to Antioch, but he died in the spring of 1143 following a hunting accident. Raymond was emboldened to invade Cilicia, but he was defeated and forced to go to Constantinople to beg mercy from the new emperor.^[81]

Byzantine Empire in purple, c.1180, at the end of the Komnenian period

John's chosen heir was his fourth son, Manuel I Komnenos, who campaigned aggressively against his neighbours both in the west and in the east. In Palestine, he allied himself with the Crusader Kingdom of Jerusalem and sent a large fleet to participate in a combined invasion of Fatimid Egypt. Manuel reinforced his position as overlord of the Crusader states, with his hegemony over Antioch and Jerusalem secured by agreement with Raynald, Prince of Antioch, and Amalric, King of Jerusalem respectively.^[82] In an effort to restore Byzantine control over the ports of southern Italy, he sent an expedition to Italy in 1155, but disputes within the coalition led to the eventual failure of the campaign. Despite this military setback, Manuel's armies successfully invaded the Kingdom of Hungary in 1167, defeating the Hungarians at the Battle of Sirmium. By 1168 nearly the whole of the eastern Adriatic coast lay in Manuel's hands.^[83] Manuel made several alliances with the Pope and Western Christian kingdoms, and successfully handled the passage of the Second Crusade through his empire.^[84] Although hopes for a lasting Papal-Byzantine alliance came up against insuperable problems, Pope Innocent III clearly had a positive view of Manuel when he told Alexios III that he should imitate "your predecessor Manuel of famous memory" who "always replied favourably to ourselves and our predecessors".^[85]

In the east, however, Manuel suffered a major defeat at the Battle of Myriokephalon, in 1176, against the Turks. Yet the losses were quickly made good, and in the following year Manuel's forces inflicted a defeat upon a force of "picked Turks".^[86] The Byzantine commander John Vatatzes, who destroyed the Turkish invaders at the Battle of Hyelion and Leimocheir, not only brought troops from the capital but also was able to gather an army along the way; a sign that the Byzantine army remained strong and that the defensive program of western Asia Minor was still successful.^[87]

12th century Renaissance

John and Manuel pursued active military policies, and both deployed considerable resources on sieges and on city defenses; aggressive fortification policies were at the heart of their imperial military policies.^[88] Despite the defeat at Myriokephalon, the policies of Alexios, John and Manuel resulted in vast territorial gains, increased frontier stability in Asia Minor, and secured the stabilization of the empire's European frontiers. From c.1081 to c.1180, the Komnenian army assured the empire's security, enabling Byzantine civilization to flourish.^[89]

This allowed the Western provinces to achieve an economic revival which continued until the close of the century. It has been argued that Byzantium under the Komnenian rule was more prosperous than at any time since the Persian invasions of the 7th century. During the 12th century population levels rose and extensive tracts of new agricultural land were brought into production. Archaeological evidence from both Europe and Asia Minor shows a considerable increase in the size of urban settlements, together with a notable upsurge in new towns. Trade was also flourishing; the Venetians, the Genoese and others opened up the ports of the Aegean to commerce, shipping goods from the Crusader kingdoms of Outremer and Fatimid Egypt to the west and trading with the Byzantine Empire via Constantinople.^[90]

In artistic terms, there was a revival in mosaic, and regional schools of architecture began producing many distinctive styles that drew on a range of cultural influences.^[91] During the 12th century the Byzantines provided their model of early humanism as a renaissance of interest in classical authors. In Eustathius of Thessalonica Byzantine humanism found its most characteristic expression.^[92]

Decline and disintegration

Dynasty of the Angeloi and Third Crusade

Manuel's death on 24 September 1180 left his 11-year-old son Alexios II Komnenos on the throne. Alexios was highly incompetent at the office, but it was his mother, Maria of Antioch, and her Frankish background that made his regency unpopular.^[94] Eventually Andronikos I Komnenos, a grandson of Alexios I, launched a revolt against his younger relative and managed to overthrow him in a violent coup d'état. Utilizing his good looks and his immense popularity with the army, he marched on to Constantinople in August 1182, and incited a massacre of the Latins.^[95] After eliminating his potential rivals, he had himself crowned as co-emperor in September 1183; he eliminated Alexios II and even took his 12-year-old wife Agnes of France for himself.^[95]

This troubled succession weakened the dynastic continuity and solidarity on which the strength of the Byzantine state had come to rely.^[96] The new emperor was a man of astounding contrasts.^[96] Handsome and eloquent, Andronikos was at the same time known for his licentious exploits.^[97] Energetic, able and determined, he had been called a "true Komnenos".^[98] However, he was also capable of terrifying brutality, violence and cruelty.^[96]

Andronikos began his reign well; in particular, the measures he took to reform the government of the empire have been praised by historians. According to George Ostrogorsky, Andronikos was determined to root out corruption: Under his rule the sale of offices ceased; selection was based on merit, rather than favoritism; officials were paid an adequate salary so as to reduce the temptation of bribery. In the provinces Andronikos' reforms produced a speedy and marked improvement.^[96] The people felt the severity of his laws, but acknowledged their justice, and found themselves protected from the rapacity of their superiors.^[96] Andronikos' efforts to rein in the oppressive tax collectors and officials of the empire did much to alleviate the lot of the peasantry, but his attempt to check the power of the nobility was considerably more problematic. The aristocrats were infuriated against him, and to make matters worse, Andronikos seems to have become increasingly unbalanced; executions and violence became increasingly common, and his reign turned into a reign of terror.^[99] Andronikos seemed almost to seek the extermination of the aristocracy as a whole. The struggle against the aristocracy turned into wholesale slaughter, while the emperor resorted to ever more ruthless measures to shore up his regime.^[96]

Despite his military background, Andronikos failed to deal with Isaac Komnenos, Béla III who reincorporated Croatian territories into Hungary, and Stephen Nemanja of Serbia who declared his independence from Byzantium. Yet none of these troubles would compare to William II of Sicily's invasion force of 300 ships and 80,000 men, arriving in 1185.^[100] Andronikos mobilized a small fleet of 100 ships to defend the capital but other than that he was indifferent to the populace. He was finally overthrown when Isaac Angelos, surviving an imperial assassination attempt, seized power with the aid of the people and had Andronikos killed.^[101]

Iconium is won by the Third Crusade.

Fourth Crusade

The Entry of the Crusaders into Constantinople, by Eugène Delacroix (1840, oil on canvas, 410 x 498 cm, Louvre, Paris).

After the death of Theobald III, Count of Champagne, the leadership of the Crusade passed to Boniface of Montferrat, a friend of the Hohenstaufen Philip of Swabia. Both Boniface and Philip had married into the Byzantine imperial family. In fact, Philip's brother-in-law, Alexios Angelos, son of the deposed and blinded emperor Isaac II Angelos, had appeared in Europe seeking aid and had made contacts with the crusaders. Alexios offered to reunite the Byzantine church with Rome, pay the crusaders 200,000 silver marks, and join the crusade with 200,000 silver marks and all the supplies they needed to get to Egypt.^[109] Innocent was aware of a plan to divert the Crusade to Constantinople, and forbade any attack on the city; but the papal letter arrived after the fleets had left Zara.

Alexios III made no preparations for the defense of the city; thus, when the Venetian fleet entered the waters of C