Byzantine Empire (Behind the Bionics)

Early History
The Roman army succeeded in conquering many territories covering the Mediterranean region and coastal regions in southwestern Europe and north Africa. These territories were home to many different cultural groups, both urban populations and rural populations. Generally speaking, the eastern Mediterranean provinces were more urbanised than the western, having previously been united under the Macedonian Empire and Hellenised by the influence of Greek culture.

The West also suffered more heavily from the instability of the 3rd century AD. This distinction between the established Hellenised East and the younger Latinised West persisted and became increasingly important in later centuries, leading to a gradual estrangement of the two worlds.

An early instance of the partition of the Empire into East and West occurred in 293, when Emperor Diocletian created a new administrative system (the tetrarchy), to guarantee security in all endangered regions of his Empire. He associated himself with a co-emperor (Augustus), and each co-emperor then adopted a young colleague given the title of Caesar, to share in their rule and eventually to succeed the senior partner. Each tetrarch was in charge of a part of the Empire. The tetrarchy collapsed, however, in 313 and a few years later Constantine I reunited the two administrative divisions of the Empire as sole Augustus.

Christianization and partition of the Empire
In 330, Constantine moved the seat of the Empire to Constantinople, which he founded as a second Rome on the site of Byzantium, a city strategically located on the trade routes between Europe and Asia and between the Mediterranean and the Black Sea. Constantine introduced important changes to the Empire's military, monetary, civil and religious institutions. In regards to his economic policies he has been accused by certain scholars of "reckless fiscality", but the gold solidus he introduced became a stable currency that transformed the economy and promoted development.

Under Constantine, Christianity did not become the exclusive religion of the state, but enjoyed imperial preference since he supported it with generous privileges. Constantine established the principle that emperors could not settle questions of doctrine on their own, but should summon instead general ecclesiastical councils for that purpose. His convening of both the Synod of Arles and the First Council of Nicaea indicated his interest in the unity of the Church, and showcased his claim to be its head.[27] The rise of Christianity was briefly interrupted on the accession of the emperor Julian in 361, who made a determined effort to restore polytheism throughout the empire and was thus dubbed "Julian the Apostate" by the Church. However, this was reversed when Julian was killed in battle in 363.[29]

Theodosius I (379–395) was the last Emperor to rule both the Eastern and Western halves of the Empire. In 391 and 392 he issued a series of edicts essentially banning pagan religion. Pagan festivals and sacrifices were banned, as was access to all pagan temples and places of worship. The last Olympic Games are believed to have been held in 393. In 395, Theodosius I bequeathed the imperial office jointly to his sons: Arcadius in the East and Honorius in the West, once again dividing Imperial administration. In the 5th century the Eastern part of the empire was largely spared the difficulties faced by the West – due in part to a more established urban culture and greater financial resources, which allowed it to placate invaders with tribute and pay foreign mercenaries. This success allowed Theodosius II to focus on the codification of Roman law and further fortification of the walls of Constantinople, which left the city impervious to most attacks until 1453. Large portions of the Theodosian Walls are preserved to the present day.

To fend off the Huns, Theodosius had to pay an enormous annual tribute to Attila. His successor, Marcian, refused to continue to pay the tribute, but Attila had already diverted his attention to the Western Roman Empire. After Attila's death in 453, the Hun Empire collapsed, and many of the remaining Huns were often hired as mercenaries by Constantinople.

Loss of the Western Roman Empire
After the fall of Attila, the Eastern Empire enjoyed a period of peace, while the Western Empire continued to deteriorate due to the expanding migration and invasions of the "barbarians", most prominently the Germanic nations. The West's end is usually dated 476 when the East Germanic Roman foederati general Odoacer deposed the Western Emperor Romulus Augustulus, a year after the latter usurped the position from Julius Nepos.

In 480 with the death of the Julius Nepos, Eastern Emperor Zeno became sole claimant to Emperor of the empire. Odoacer, now ruler of Italy, was nominally Zeno's subordinate but acted with complete autonomy, eventually providing support to a rebellion against the Emperor.

Zeno negotiated with the invading Ostrogoths, who had settled in Moesia, convincing the Gothic king Theodoric to depart for Italy as magister militum per Italiam ("commander in chief for Italy") with the aim of deposing Odoacer. By urging Theodoric to conquer Italy, Zeno rid the Eastern Empire of an unruly subordinate (Odoacer) and moved another (Theodoric) further from the heart of the Empire. After Odoacer's defeat in 493, Theodoric ruled Italy de facto, although he was never recognised by the eastern emperors as "king" (rex).

In 491, Anastasius I, an aged civil officer of Roman origin, became Emperor, but it was not until 497 that the forces of the new emperor effectively took the measure of Isaurian resistance. Anastasius revealed himself as an energetic reformer and an able administrator. He introduced a new coinage system of the copper follis, the coin used in most everyday transactions. He also reformed the tax system and permanently abolished the chrysargyron tax. The State Treasury contained the enormous sum of 320,000 lb (150,000 kg) of gold when Anastasius died in 518.

Trouble with the East
In 620, Egypt declared independence from the Byzantine Empire. Meanwhile, the Arabs fought the Byzantines over Jerusalem for the next four centuries.

Religious dispute over iconoclasm
The 8th and early 9th centuries were also dominated by controversy and religious division over Iconoclasm, which was the main political issue in the Empire for over a century. Icons (here meaning all forms of religious imagery) were banned by Leo and Constantine from around 730, 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 worshiped. Irene is said to have endeavoured to negotiate a marriage between herself and Charlemagne, but, according to Theophanes the Confessor, the scheme was frustrated by Aetios, one of her favourites.

In the early 9th century, Leo V reintroduced the policy of iconoclasm, but in 843 empress Theodora restored the veneration of icons with the help of Patriarch Methodios. Iconoclasm played a part in the further alienation of East from West, which worsened during the so-called Photian schism, when Pope Nicholas I challenged the elevation of Photios to the patriarchate.

Wars against the Bulgarian Empire
The withdrawal of large numbers 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 Asia Minor, many cities shrank to small fortified settlements. In the 670s, the Bulgars were pushed south of the Danube by the arrival of the Khazars. In 680, Byzantine forces sent to disperse these new settlements were defeated.

The traditional struggle with the See of Rome continued through the Macedonian Dynasty, spurred by the question of religious supremacy over the newly Christianised state of Bulgaria. Ending eighty years of peace between the two states, the powerful Bulgarian Tsar Simeon I invaded in 894 but was pushed back by the Byzantines, who used their fleet to sail up the Black Sea to attack the Bulgarian rear, enlisting the support of the Hungarians. The Byzantines were defeated at the Battle of Boulgarophygon in 896, however, and agreed to pay annual subsidies to the Bulgarians.

Leo the Wise died in 912, and hostilities soon resumed as Simeon marched to Constantinople at the head of a large army. Although the walls of the city were impregnable, the Byzantine administration was in disarray and Simeon was invited into the city, where he was granted the crown of basileus (emperor) 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. The Empire now faced the problem of a powerful Christian state within a few days' marching distance from Constantinople, as well as having to fight on two fronts.

A great imperial expedition under Leo Phocas and Romanos I Lekapenos ended with another crushing Byzantine defeat at the Battle of Achelous in 917, and the following year the Bulgarians were free to ravage northern Greece. Adrianople was plundered again in 923, and a Bulgarian army laid siege to Constantinople in 924. Simeon died suddenly in 927, however, and Bulgarian power collapsed with him. In 968, Bulgaria was overrun by the Rus' under Sviatoslav I of Kiev, but three years later, John I Tzimiskes defeated the Rus' and re-incorporated Eastern Bulgaria into the Byzantine Empire

Bulgarian resistance revived under the rule of the Cometopuli dynasty, but the new Emperor Basil II ( r . 976–1025) made the submission of the Bulgarians his primary goal. Basil's first expedition against Bulgaria, however, resulted in a defeat at the Gates of Trajan. For the next few years, the emperor would be preoccupied with internal revolts in Anatolia, while the Bulgarians expanded their realm in the Balkans. The war dragged on for nearly twenty years. The Byzantine victories of Spercheios and Skopje decisively weakened the Bulgarian army, and in annual campaigns, Basil methodically reduced the Bulgarian strongholds. At the Battle of Kleidion in 1014 the Bulgarians were annihilated: their army was captured, and it is said that 99 out of every 100 men were blinded, with the hundredth man left with one eye so he could lead his compatriots home. When Tsar Samuil saw the broken remains of his once formidable army, he died of shock. By 1018, the last Bulgarian strongholds had surrendered, and the country became part of the Empire. This victory restored the Danube frontier, which had not been held since the days of the Emperor Heraclius.

Relations with the Kievan Rus'
Between 850 and 1100, the Empire developed a mixed relationship with the new state of the Kievan Rus', which had emerged to the north across the Black Sea. This relationship would have long-lasting repercussions in the history of the East Slavs, and the Empire quickly became the main trading and cultural partner for Kiev. The Rus' launched their first attack against Constantinople in 860, pillaging the suburbs of the city. In 941, they appeared on the Asian shore of the Bosphorus, but this time they were crushed, an indication of the improvements in the Byzantine military position after 907, when only diplomacy had been able to push back the invaders. Basil II could not ignore the emerging power of the Rus', and, following the example of his predecessors, he used religion as a means for the achievement of political purposes. Rus'–Byzantine relations became closer following the marriage of Anna Porphyrogeneta to Vladimir the Great in 988, and the subsequent Christianisation of the Rus'. Byzantine priests, architects, and artists were invited to work on numerous cathedrals and churches around Rus', expanding Byzantine cultural influence even further, while numerous Rus' served in the Byzantine army as mercenaries, most notably as the famous Varangian Guard.

Split between Orthodoxy and Catholicism (1054)
In 1054, relations between the Eastern and Western traditions of the Chalcedonian Christian Church reached a terminal crisis, known as the East–West Schism. 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.

=== Crisis and fragmentation === The Byzantine Empire soon fell into a period of difficulties, caused to a large extent by the undermining of the theme system and the neglect of the military. Nikephoros II, John Tzimiskes, and Basil II shifted the emphasis of the military divisions (τάγματα, tagmata) from a reactive, defence-oriented citizen army into an army of professional career soldiers, increasingly dependent on foreign mercenaries. Mercenaries were expensive, however, and as the threat of invasion receded in the 10th century, so did the need for maintaining large garrisons and expensive fortifications. Basil II left a burgeoning treasury upon his death, but he neglected to plan for his succession. None of his immediate successors had any particular military or political talent and the imperial administration increasingly fell into the hands of the civil service. Incompetent efforts to revive the Byzantine economy resulted in severe inflation and a debased gold currency. The army was now seen as both an unnecessary expense and a political threat. A number of standing local units were demobilised, further augmenting the army's dependence on mercenaries, who could be retained and dismissed on an as-needed basis.

At the same time, Byzantium was faced with new enemies. In 1048-9, the Seljuk Turks under Ibrahim Yinal made their first incursion into the Byzantine frontier region of Syria and defeated a Byzantine army of 50,000 at the Battle of Kapetrou on 10 September 1048. The Arab chronicler Ibn al-Athir reports that Ibrahim brought back 100,000 captives and a vast booty loaded on the backs of ten thousand camels.

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 the Battle of Manzikert, Romanos suffered a surprise defeat by Sultan Alp Arslan, and he was captured. Alp Arslan treated him with respect and imposed no harsh terms on the Byzantines.[113] In Constantinople, however, a coup put in power Michael Doukas, who soon faced the opposition of Nikephoros Bryennios and Nikephoros Botaneiates. By 1081, the Seljuks had expanded their rule over virtually the entire Anatolian plateau from Armenia in the east to Bithynia in the west, and they had founded their capital at Nicaea, just 90 kilometres (56 miles) from Constantinople.

Alexios I and the First Crusade
After Manzikert, a partial recovery (referred to as the Komnenian restoration) was made possible by the Komnenian dynasty. The Komnenoi attained power again under Alexios I in 1081. From the outset of his reign, Alexios faced a formidable attack by the Normans under Robert Guiscard and his son Bohemund of Taranto, who captured Dyrrhachium and Corfu, and laid siege to Larissa in Thessaly. Robert Guiscard's death in 1085 temporarily eased the Norman problem. The following year, the Seljuq sultan died, and the sultanate was split by internal rivalries. By his own efforts, Alexios defeated the Pechenegs; they were caught by surprise and annihilated at the Battle of Levounion on 28 April 1091.

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.[126] 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, envoys from Alexios 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 Alexios's request as a dual opportunity to cement Western Europe and reunite the Eastern Orthodox Church with the Roman Catholic Church under his rule. 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.

Alexios had anticipated help in the form of mercenary forces from the West, but he was totally unprepared for the immense and undisciplined force that soon arrived in Byzantine territory. It was no comfort to Alexios 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 reconquer from the Turks on their way to the Holy Land. In return, he gave them guides and a military escort

Alexios was able to recover a number of important cities and islands, and in fact much of western Asia Minor. The Crusaders agreed to become Alexios' vassals under the Treaty of Devol in 1108, which marked the end of the Norman threat during Alexios' reign.

John II, Manuel I and the Second Crusade
Alexios's son John II Komnenos succeeded him in 1118 and ruled until 1143. John was a pious and dedicated Emperor who was determined to undo the damage to the empire suffered at the Battle of Manzikert, half a century earlier. 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. For this reason, he has been called the Byzantine Marcus Aurelius.

During his twenty-five-year reign, John made alliances with the Holy Roman Empire in the West and decisively defeated the Pechenegs at the Battle of Beroia. He thwarted Hungarian and Serbian threats during the 1120s, and in 1130 he allied himself with the German emperor Lothair III against the Norman king Roger II of Sicily.

In the later part of his reign, John focused his activities on the East, personally leading numerous campaigns against the Turks in Asia Minor. His campaigns fundamentally altered the balance of power in the East, forcing the Turks onto the defensive, while restoring many towns, fortresses, and cities across the peninsula to the Byzantines. He defeated the Danishmend Emirate of Melitene and reconquered all of Cilicia, while forcing Raymond of Poitiers, Prince of Antioch, to recognise Byzantine suzerainty. In an effort to demonstrate the Emperor's role as the leader of the Christian world, John marched into the Holy Land at the head of the combined forces of the Empire and the Crusader states; yet despite his great vigour pressing the campaign, his hopes were disappointed by the treachery of his Crusader allies. In 1142, John returned to press his claims to Antioch, but he died in the spring of 1143 following a hunting accident.