"The whole city [of Constantinople] is full of [arguments about Theology], the squares, the market places, the cross-roads, the alleyways; old-clothes men, money changers, food sellers: they are all busy arguing. If you ask someone to give you change, he philosophizes about the Begotten and the Unbegotten; if you inquire about the price of a loaf, you are told by way of reply that the Father is greater and the Son inferior; if you ask 'Is my bath ready?' the attendant answers that the Son was made out of nothing."
—St. Gregory of Nyssa, On the Deity of the Son
The Eastern Roman Empire was the direct continuation of The Roman Empire, continuing its legacy into the Middle Age. In essence, it was the Greek-speaking Eastern part of Rome that was left standing after the barbarian invasions of the 5th century, prospering and surviving numerous ordeals until the Turks finally finished it off in 1453. The name "Byzantine" as we know today was coined, posthumously, by a German historian named Hieronymus Wolf in 1557, after the capital Byzantium, later Constantinople. The empire/kingdom called itself Roman to the very end, or in Medieval Greek: Βασιλεία Ῥωμαίων (Basileía Rhōmaíōn) "Roman Empire". The short form of the name was simply Ῥωμανία (Rhōmanía - not to be confused with thatRomania); its inhabitants were "Rhōmaíōi", or Romans.
Other forms of its name include: Βασιλεία τῶν Ῥωμαίων (Basileía tôn Rhōmaíōn - "Empire of the Romans"), Ἀρχὴ τῶν Ῥωμαίων (Arche tôn Rhōmaíōn), Πολιτεία τῶν Ῥωμαίων (Politeίa tôn Rhōmaíōn - "Roman Republic"), and also Γραικία (Graikía) and Ῥωμαΐς (Rhōmaís). And of course, there was the obligatory Latin names: Imperium Romanum, Imperium Romanorum, Res Publica Romana.
Despite all that, the Empire gradually transitioned more and more into a Greek one. Greek, having been the language of Eastern Rome since antiquity, overtook Latin as the administrative language too. Greek Orthodox Christianity was the state religion, and high Romano-Hellenistic traditions of science and literature continued unbroken, though with a Christian overtone.
Also note that, as Byzantine and Rome were, in fact, one, any "founding" date of the medieval empire is completely artificial. There are two dates frequently used by modern historians: 324, the year Emperor Constantine I moved his capital to "New Rome" Constantinople, and 395, when the Roman Empire was formally divided into Western and Eastern halves.
For most of its lifetime, the Empire consisted of the Balkan peninsula and Asia Minor. Despite that, the Byzantine Empire was still the largest, wealthiest, and most stable state in the European-Near East World for most of its history. Inheriting Roman military philosophy and discipline, Byzantium maintained, at least initially, a highly effective army based on heavy cavalry and professional infantry, and it was the undisputed naval power of Europe in The Low Middle Ages, with its infamous "Greek Fire", whose chemical components are still unknown today. Thanks to this, the Empire is often compared to a cork stopping Islam from pouring into Europe. As time went on, however, it lost more and more territory to foes, and its armed force became increasingly outdated and diluted, though there were various resurgences, such as the Komnenian Restoration.
Each Byzantine emperor naturally bestowed on himself the title of Roman Emperor, though this was greatly challenged by the Vatican, who insisted on calling him Imperator Romaniæ ("Emperor of Romania")note the Pope reserved "Imperator Romanorum" for Charlemagne and later Holy Roman Emperors but mainly Imperator Graecorum (Emperor of the Greeks) and the Byzantine empire as Imperium Graecorum, Graecia, Terra Graecorum or even Imperium Constantinopolitanum. Some notable lines of rulers are: the Justinian family, which saw the largest extent of Roman territory after the fall of the West, the Macedonian dynasty, boasting Basileios II "Bulgar Slayer", the Komnenoi, with Alexios I Komnenos, Ioannes II Komnenos, and Manuel I Kommenos, and finally the Palaiologoi, which restored the kingdom from the mess caused by the Crusaders and defiantly carried on until the Fall of Constantinople. Men didn't have all the fun to themselves - there were powerful female figures as well, like Theodora and Irene of Athens. Political rivals had a curious tradition of mutilating their opponent's faces note The Emperor was the representative of God, and as such had to be unblemished. Apart from gouging out eyes, castration was also popular, also because it prevented the victims from fathering other claimants. .
As the premier economy and culture of Europe, Byzantium was partly responsible for the Italian Renaissance, as scholars and craftsmen fled the shrinking kingdom in the 15th century. Romanesque and Ottoman architecture? Byzantium-inspired. Also, Byzantine silk was the first ever in Europe and very smexy - again, the Italians were their students and successors.
Speaking of succession, you might ask what has become of the Byzantine identity. Well, Greek people nowadays still consider Byzantium to be the medieval incarnation of Greece, some even go as far as demanding Istanbul, nay, Constantinople and Asia Minor back from Turkey. For a while, Russians saw themselves as the spiritual successors of Constantinople too, what with being Orthodox and all (and the czars being related to the Byzantine emperors by marriage), would call Russia's Moscow The "Third Rome" and adopt many Byzantine symbols such as the double-headed eagle.
Justinian (527 - 565): Emperor in Constantinople, he reconquered much of what had been the western Empire. Also known for compiling Roman law in the Corpus Juris Civilis which became the basis for law in civil law jurisdictions, employing the great general Belisarius who was the last Roman commander to be awarded a Triumph, building the splendid Hagia Sophia, dealing with chariot-racing hooliganism, and being married to cunning ex-"dancer" Theodora. Last Roman Emperor to natively speak Latin.
Maurice (582 - 602): Spent virtually his whole reign at war holding the empire together. He supported Khosrau II's claim to the Persian throne, leading to peace between the two empires upon Khosrau's accession, and the Empire receiving a hefty chunk of Armenia as a reward. He wrote the Big Book of War of his era, the Strategikon. All hell broke loose when he died.
Phocas (602 - 610): Arguably the worst emperor in the 1,480-year-long history of the Roman Empire. Assassinated Emperor Maurice and his whole family, leading to Khosrau II declaring war in revenge. The Avars and Slavs also invaded the Balkans. He started a reign of terror in Constantinople, and was responsible for the rise of mutilation as a political tactic. When he died, the Empire was on the brink of collapse.
Heraclius (610-641): Changed the official language of the Empire to Greek. Much of the empire being overrun by Persian forces, he led a heroic campaign to reconquer all of it. He succeeded, only to see those same territories lost to the Muslim Arabs. His reign wasn't pointless, though. The territories lost to the Arabs were smaller than the losses to the Persians, who had overrun almost the entire empire, as opposed to the Arabs, who "only" took about half of it.
Konstantinos III (641): Briefly succeeded his father, Heraclius, for four months before his death at the age of 28. His stepmother Martina was accused of murdering him; both she and her son Heraklonas were mutilated and exiled. Konstantinos III's eleven-year-old son Constans succeeded him as emperor.
Constans II (641-668): An unpopular emperor, who was unsuccessful in war against the Arabs and had to pay off the caliph to stop him from advancing further into Byzantine territory. During his reign, Egypt was lost to the empire forever. He is best known for being the first emperor to visit Rome in 200 years, and for stripping the city of its gold and jewels (including from the Pantheon) and hauling the riches back to Constantinople. He was so hated by the citizenry that he eventually abandoned Constantinople for Syracuse. A servant assassinated him in his bath by hitting him over the head with a soap box.
Konstantinos IV (668-685): Ruled jointly with his brothers Heraklios and Tiberios before having their noses cut off and depriving them of their imperial titles. He died aged thirty-three, leaving the throne to his son, Justinian II.
Justinian II (685-695, 705-711): His despotic rule led to him being ousted in a palace coup, mutilated, and exiled. He escaped to the Khazars (a nomadic tribe of Turkic-speaking Jews), married their khan's sister, and when his brother-in-law agreed to assassinate him (having been bought off by the usurper emperor Tiberios III) Justinian strangled the would-be assassins with his own hands. He escaped the Khazars, vowed revenge on everyone who'd wronged him, and alongside his new allies, the Bulgars, returned to Constantinople in 705 and snuck in via an obscure aqueduct, thus regaining his throne. He captured the two men responsible for his deposition, Leontios and the aforementioned Tiberios, had them trussed and used them as foostools before executing them. He then turned on his former allies, plunged the empire into war, and was deposed and murdered. Has the honor of being a Badass Of The Week.
Leo III the Isaurian (717 - 741): He stopped the Arabs at the walls of Constantinople in 717. An interesting fellow, who had lived at the eastern edge of the Empire and spoke Arabic, he became convinced that the reason for the Empire's recent defeats was divine punishment—specifically, the consistent disregard for the Second Commandment ("Thou shalt not make any graven image") in the form of icons (the Muslims hewed to this particular commandment very closely). Thus began the campaign of iconoclasm, or image-breaking, by forbidding the veneration of images. This led to instability throughout the Empire, and more significantly, induced the Pope in Rome to act more independently, eventually resulting in the Great Schism some 300 years later.
Irene (797 - 802): Reigned 780-90 as a regent for her son, then on her own after she had him blinded after he displayed iconoclastic tendencies (she was a fervent iconodoulenote The opposite of the other thing). This caused The Pope to crown Charlemagne emperor.
Nikephoros I (802-811): An all-around disaster as emperor. Fought a war with Charlemagne, the new Augustus in the West, over Venice, which only ended in a stalemate after his death. Also lost a war with the Abbasid caliphate of Baghdad, the low point of which was a humiliating battle in which the Byzantine army was routed by a Muslim force barely more than a tenth of its size. Once peace was finally made with the Muslims, Nikephoros turned his eye on the Bulgars to the north, and brutally sacked the Bulgar capital of Pliska. When he and his troops finally left the city, they were ambushed and almost annihilated by a Bulgar army. He was so hated by now that both sides claim to have killed him. Whatever the truth, most sources agree that the Bulgar Khan Krum came into possession of Nikephoros' skull, which he coated in silver and used as a drinking cup.
Mikhael III (842-867): Became emperor at the age of two. A drunk and a wastrel, Mikhael and his special friend Basil conspired to murder Mikhael's uncle and regent, Bardas. Mikhael and Basil then lived in an odd foursome with Mikhael's sister Thekla and Basil's wife, Eudokia Ingerine (who was also Mikhael's mistress) until Basil grew jealous of another courtier's influence on Mikhael and had them both assassinated.
Basil I (867-886): Called "The Macedonian" although he was, confusingly, of Armenian parentage, Basil was a peasant who's fine physique and lack of scruples brought him to the attention of the Emperor Mikhael III. He assassinated Mikhael, took the throne, and despite these inauspicious beginnings, proved to be an able politician and lawmaker. He despised his second son, Leo, whom he imprisoned and very nearly had killed before Basil died in a "hunting accident", the only witness to which was the father of Leo's girlfriend (and later wife) Zoe.
Leo VI the Philosopher (886-912): Best remembered today for his bizarre paternity and the scandal created by his four marriages. Leo's mother was the mistress of Emperor Mikhael III and the wife of Emperor Basil I, and its still debated as to which of them fathered Leo (his own mother may not have known). His first three wives died without giving him a male heir so Leo married his mistress after she gave birth to a son (the future Konstantinos VII) enraging church leaders who believed that successive marriages were illegal. Had a reputation as not only very wise, but also as something of a prophet and magician.
Konstantinos VII (913-959): Son of Leo VI and nephew of the Emperor Alexander, and son-in-law of Romanos I. Konstantinos referred to himself as "Konstantinos Porphyrogennetos" (Latinized as "Constantine Porphyrogenitus") to elevate himself above other claimants to the Roman throne. Konstantinos was a scholar and an artist, and during his reign Byzantium prospered in what has come to be known as the "Macedonian Renaissance".
Romanos II (959-963): After the death of his first wife, Bertha of Italy, Romanos got his father, the emperor Konstantinos VII, to promise that he would be allowed to choose his own second wife. Romanos fell in love with the beautiful daughter of an innkeeper and married her, much to his father's horror. She became known as Theophano. He died at the age of 25, leaving Theophano and three young children.
Nikephoros II Phokas (963-969): A brilliant general who married the widowed empress Theophano shortly after the death of her husband, Romanos II. Theophano began an affair with his nephew, Ioannes Tzimiskes, and they assassinated Nikephoros and paraded his head around on a spike. On his coffin was carved: You conquered all but a woman.
Ioannes I Tzimiskes (969-976): After assassinating his uncle Nikephoros, Ioannes exiled his lover (and Nikephoros' widow) Theophano, then married Theodora, a sister of the late emperor Romanos. A successful general in his own right, he died suddenly while returning home from campaigning against the Abbasid Empire. Legend has it that he was poisoned by a courtier. He was succeeded by Basil, son of Romanos II and Theophano.
Basil II the Bulgar-slayer (976 - 1025): Expanded the Empire to its greatest extent since the Arab invasions. He gained his fearsome moniker by ruthlessly subduing Bulgaria, and allegedly blinding 99 out of every 100 Bulgar captives after a major battle, which led the Bulgar king to die of shock. A hyper-competent general and administrator, the Empire was the most powerful country in Europe and the Mediterranean during his reign.
Konstantinos VIII (1025-1028): Brother and successor of Basil II. Already an elderly man when he became emperor, he ruled capriciously and cruelly. He had no sons, so the empire was left to his daughters, Zoe and Theodora, and Zoe's husband, Romanos III.
Zoe (1028-1050): Daughter of Konstantinos VIII and sister of the Empress Theodora. Her father kept her and her sister from marrying until they were both almost fifty years old. From 1028 she ruled alongside her three husbands and then her sister. Her first husband, Romanos III, was found dead in his bath in 1034, and Zoe married her lover, who became the emperor Mikhael IV, later that same day. After Mikhael IV's death, Zoe's adopted son Mikhael V banished her to a monastery, but she returned after a coup removed Mikhael V from power. She was forced to share power with her sister Theodora. Hoping to diminish her sister's power, Zoe married a third time, to Konstantinos Monomakhos, who after her death continued ruling alongside Theodora.
Konstantinos IX Monomakhos (1042-1055): Co-ruler with his wife Zoe (who was about twenty years older than him). Militarily he was a weak ruler and during his reign the religious schism between Constantinople and Rome resulted in the splitting of the church into the Eastern (Greek) and Western (Latin) branches.
Theodora (1042-1056): The younger sister of Zoe, Theodora was much plainer than the beautiful Zoe but also more intelligent and determined. She never married nor had children; shortly before her death she chose Mikhael Bringas as her successor.
Romanos IV Diogenes (1068–1071) By far most famous for the Battle of Manzikert. He sought to decisively defeat the leader of the Seljuk Turks and thus stop the bandit raids on the eastern borderlands, which would have been a better idea if Sultan Alp Arslan was the least bit interested in attacking the Romaioinote (the Fatamid heretics in Egypt was his fixation to the extent that anything was) and/or the bandits doing the raiding even pretended to acknowledge his authority. Moreover, the implementation of the plan would have gone rather better had one of Romanos' commanders not vanished with a third of the army before the battle and another not spread rumors of his fall during it.
Wounded and captured, Romanos IV was the first Roman Emperor to be a POW in over eight centuries. His captor, once the ritual boot-on-neck thing was done with, was quite chivalrous about the matter; treating him as an honored guest, negotiating an affordable ransom, securing minor border adjustments, and providing Romanos an escort 'fit for an emperor' to return to Constantinople. Cue civil war, deposition, blinding, death, more civil war, nomadic Turks wandering into what had been reduced to sheep pasture over the past few decades, said Turks being hired to deal with one faction or another, etc....
Alexios I Komnenos (1081 - 1118): Appealed to the Pope and the western European kingdoms for assistance against the Turks, leading to The Crusades. Halted the Empire's sharp decline after the disastrous Battle of Manzikert, at least for a while.
Ioannes II Komnenos (1118-1143): Son of Manuel I, and brother of Anna Komnene, author of The Alexiad (she despised him and tried to seize the throne from him). A strict but moral ruler, and a successful general and diplomat.
Manuel I Komnenos (1143 - 1180): Youngest son of Ioannes II, but became emperor due to a prophecy. Pursued an aggressive foreign policy and expanded the Empire, but his conquests didn't last long.
Alexios II Komnenos (1180-1183): He was eleven-years-old when his father, Manuel I, died. His father's cousin Andronikos Komnenos became regent, removed Alexios' mother and her supporters from power, and eventually had Alexios II himself strangled with a bow-string. Alexios' mother, sister, and most of the rest of his relatives would die at Andronikos' hands.
Andronikos I Komnenos (1183-1185): Ne'er-do-well cousin of Manuel I, he took over as regent for Manuel's underage son, Alexios II, and then killed the boy, the dowager empress, and most of the rest of the imperial family while he was at it. He also married Alexios II's child-widow, Princess Agnes of France, even though he was past sixty and she was only eleven. Tried to flee the city in panic after the commoners revolted in support of his cousin Isaakios Angelos, but was captured, brutally tortured, and executed. His sons were killed as well, but two grandsons survived and eventually founded the independent state of Trebizond in 1204.
Isaakios II Angelos (1185-1195, 1203-1204): A distant cousin of his predecessor Andronikos I, he came to the throne due a bizarre fluke (he killed an official who'd come to arrest him; in the ensuing chaos, Andronikos tried to flee, was captured and executed, and Isaakios took his place). His adored brother, Alexios, repaid his trust by staging a coup, blinding him, and stealing his crown. Briefly returned to power after the Fourth Crusade ousted Alexios III in 1203. He quarreled with his son and co-ruler, Alexios IV, and became paranoid and obsessed with regaining his lost sight. Died of shock when his son was murdered by the usurper Alexios Mourtzophlos.
Alexios III Angelos (1195-1203): Brother and usurper of Isaakios II. A decadent and weak ruler who bankrupted the state and let the warships rot in the harbor, when the Fourth Crusade arrived on the scene he sneaked out of the city under cover of night, abandoning his daughters and wife but taking with him what was left of the treasury. His only real ally was the Seljuk sultan Keyhüsrev, who regarded him as a surrogate father and died in battle trying to help Alexios regain his lost empire.
Alexios IV Angelos (1203-1204): Son of Isaakios II, the teenaged Alexios escaped his uncle Alexios III and made his way to Germany, where his sister Irene was empress to the Holy Roman Emperor Philipp of Swabia. He met with the pope and promised him the moon in return for the Fourth Crusade's diversion to Constantinople. After his uncle fled the city, the Crusaders set Alexios IV up as co-ruler alongside his father, but Isaakios II resented his son and thwarted him at every turn. The courtier Alexios Mourtzophlos staged a coup and murdered Alexios IV; the Crusaders attacked the city in retribution, leading to the disastrous Sack of Constantinople.
Alexios V Doukas "Mourtzophlos" (1204): A courtier who'd been imprisoned by Alexios III for romancing the emperor's daughter, Eudokia. Though freed by Alexios IV, he nevertheless turned on the young emperor, killed him, and declared himself emperor. He fled Constantinople when the Crusaders attacked. While exiled, he joined up with his father-in-law, Alexios III, who treacherously blinded him and left him for the Crusaders to find. He was executed by being thrown from the top of the Column of Theodosios. He was the last Greek, or Byzantine, emperor to rule Constantinople for 57 years, until the accession of Mikhael VIII Palaiologos. His nickname, mourtzophlos, meant "hairy eyebrows".
Mikhael VIII Palaiologos (1259–1282): A great-grandson of Emperor Alexios III on his mother's side, Mikhael was brought up in the sophisticated court of the emperor of Nikaia (a Greek splinter state founded after Constantinople fell to the Crusaders in 1204). Charismatic and talented, Mikhael made himself regent for the seven-year-old boy emperor of Nikaia, Ioannes IV Doukas Laskaris. The Byzantines recaptured Constantinople in 1261, pouring in through an unlocked gate in the city walls (yes, really) and Mikhael took the opportunity to crown himself and his infant son Andronikos as emperors. The boy-emperor Ioannes IV was quietly blinded and locked up in a monastery. A schemer and a dissembler, Mikhael helped incite the Sicilian Vespers against his enemy Charles of Anjou; assisted Pedro III of Aragon in invading Sicily; and instigated revolts in Crete against the Venetians. His dynasty would rule Constantinople until the city fell to the Turks in 1453.
Andronikos III Palaiologos (1328-1341): He accidentally murdered his own brother Manuel in 1320, having mistaken Manuel for his mistress's lover. Their father, co-emperor Mikhael IX, died of grief and their grandfather, Andronikos II, disowned him. This led to civil war between grandfather and grandson. Eventually, Andronikos III was recognized as co-emperor, and in 1328 he deposed his grandfather altogether. During his reign, Serbia and the Ottoman Turks steadily chipped away at Byzantine territory.
Konstantinos XI Palaiologos (1449 - 1453): The last emperor in the east, he led Constantinople in a heroic Last Stand against the Turks. His body was never found, elevating him to legendary status. A legend among the Greeks states that he was saved by an angel, and that he will return one day to reconquer Constantinople for the Greeks.
Tropes applicable to the Eastern Roman Empire:
Arch-Enemy: As it turned out, the Seljuk and Osman/Ottoman Turks. Before that, the Mamluk Sultanate of Egypt. Before that, the Caliphate. Before that, Persia. It also had some really nasty wars with Bulgaria for a century or two.
Also the Papacy, Venice, and the Holy Roman Emperor also had their time as the Archenemy of Rome.
Serbia as well, at least for a little while. There was one point in the thirteenth century where the odds were pretty good that Serbia could have invaded the entire empire. They failed obviously, but not from a lack of trying.
Art Evolution: Byzantine art endured through Late Antiquity and the Middle Ages. Though heading in an Oriental direction, it was very continuous and gave us the love for strong colours and intricate patterns that can still be seen in the aesthetics of Orthodox churches. And have you seen the Byzantine way of dressing reconstructed? Set quite the tone for Eastern European folk outfits, didn't it? All of that evolved more or less from the Roman tunic, with an exotic whiff from Persia.
Badass Decay: Towards the end. As more territory was lost, there simply wasn't enough economic base to gain back the wealth and power it once had.
At its worst, all that was left of the Empire was Constantinople itself and the immediate surrounding land, a few islands, and the Peloponnese peninsula. The situation was so dire that the last Emperors were officially vassals of the Ottoman Sultan.
There is no historical consensus on when the Badass Decay began. Western scholars during the Enlightenment period tended to view the entire history of the Byzantine Empire as a sad, pathetic shadow of the former Roman Empire, but more recent historians tend to emphasize the resiliency and adaptability of the Byzantine Empire, as well as its vast wealth and power it possessed during most of its history. Various periods have been proposed as the beginning of decline, including the Sassanid War (602-628), the Arab Wars (beginning 634), the arrival of the Turks and the battle of Manzikert (1071), the death of the last great Komnenian Emperor, Manuel I Komnenos (1180), and the Fourth Crusade (1204). All of these events were certainly disasters for the Byzantines, but historians disagree on where the Byzantines had declined past the point of no return. For example, the permanent loss of Alexandria to the Arabs in 641 permanently crippled the Byzantines, but their continuation as one of the most powerful nations despite the loss for at least 400 years would seem to indicate that their throat had not yet been cut. Regardless, modern historians tend to agree that the Fourth Crusade had finally put the nail in the coffin of the Byzantines, and although they would regain Constantinople, they were essentially powerless from then on.
Berserk Button: Khosrau II, emperor of Sassanid Persia, had the Empire on the ropes, winning battle after battle. Newly-crowned Emperor Heraclius was planning to ditch Constantinople and take up the less deadly job of ruling over the ruins of the probably doomed empire in North Africa. High on his own success, Khosrau sent Heraclius a letter, calling the Eastern Roman emperor his 'insensate slave' and then went on to taunt him by pointing out that Persia and its sun-worshiping religion was awesome and asked what good Jesus was if he couldn't even manage to save his own life? When the people of Constantinople heard this, they instantly transformed from whipped into extremely pissed off, Heraclius discovered a pair of testicles in his trousers, and beat the Persians back and regained lost Byzantine territory. A few years later, the burgeoning Muslim armies were able to destroy Khosrau's forces, and Sassanid Persia was conquered; Khosrau, after losing his empire was later assassinated.
Big Bad: To the Arabs, Turks, Sassanid Persians, Cumans, Rus', Magyars, Bulgarians, Serbs, and Venetians. Fought off all of them successfully (though its resources and territory suffered constant reduction, despite a few periods of resurgence) until 1204, when the Venetian-led 4th Crusade conquered Constantinople, dealing the Empire a mortal blow. Despite the recovery of Constantinople by Michael VIII Paleologos and much of the Empire's European territories, its resources had been critically depleted, and the Empire was further weakened by civil wars, internal bickering, growing economic dependence on the Venetians and Genoese, and constant two-front wars with the Bulgarians and Turks, leading to the final fall of Constantinople in 1453.
Big Book of War: Several of the most famous of these were Byzantine field manuels.
The Empire, for a thousand years, insulated Western Europe from the aforementioned nasties (Venetians and Magyars excepted, as the first is in the West, and the second were on good terms with the Pope and the Holy Roman Emperor, generally) by being essentially a huge, mighty, stable, populous, wealthy, and determined buffer state (relatively speaking). And how did the West repay the Empire's millenium of blood, toil, tears, and hardship? With the 4th Crusade.note Well before the 4th Crusader, the Pope gave the Byzantines a big slap in the face by declaring Charlemagne to be the "Roman Emperor." At the time, the Roman Empire was ruled by a woman, and thus the Pope considered it to be vacant, which made him feel capable of doing such a thing, though he had no real authority to crown a Roman Emperor. Nonetheless, it essentially kicked off the East-West schism in Christianity.Even after this blow, the Empire's many enemies spent the next two hundred or so years basically mopping up what remained of the Empire, and so it still managed to insulate the West, though it no longer posed any real threat to the Turks, Bulgarians, or Serbs.
As for the Genoese, it was enough that the Byzantines were mortal enemies of the Venetians (though the Venetians' mercenary tendencies manifested strongly, which, combined with Byzantine desperation, resulted in their working together on many occasions). The Genoese got a huge support structure, infrastructure, exploitative rights over many of the Empire's cities, major economic penetration of virtually the whole empire, and outright cessions of territory (in modern Ukraine and Bulgaria, of all places, as well as the more-intuitive Aegean). The Byzantines got military and naval support (the overall commander of Byzantine forces at the final Siege of Constantinople in 1453 was Genoese, as was the only gunpowder artillery the defenders possessed), plus tons of cash from fat Genoese merchant banks
Book Ends: Born by Constantine I, died with Constantine XI.
Also, possibly their greatest emperor was named Justinian, and the commander of the Genoese allies at the Fall of Constantinople was named Gustiniani, the Italian version of Justinian.
The Chessmaster: This reputation is a bit exagerrated, at least if one is comparing it to other states. Still there is a reason we speak of "byzantine" scheming.
Some of it is Western bias against the Byzantines, but some of it is rather justified. After all, they were for much of their history an empire that had to deal with Catholic countries that disputed their right to exist to the west and north and various militantly expansionist Islamic empires to the east and south simultaneously, so their foreign policy had to be devious.
City of Spies: It wasn't called "Byzantine" for nothing, although that term only has such connotations because it was invented by historians (never used by the Byzantines themselves) to distinguish between what were, practically speaking, phases of the Roman Empire. All of which seems somewhat recursive.
Deadly Decadent Court: As expected from a millennium-old political entity. We didn't get the word "byzantine" in English for nothing. (It's a negative stereotype held by Western Europe, granted, but still...)
Eye Scream: A particular favorite method of dealing with rivals for the throne was having their eyes put out and shipping them to a monastery to spend the rest of their days.
Basileios the Bulgar-Slayer allegedly did this to more than 14000 prisoners of war after his victory in the battle of Kleidion. One in a hundred of them was allowed to keep one eye to lead them back to the Bulgarian Tsar Samuil, who is said to have suffered a heart attack from the sight of his men.
The empress Zoe is portrayed this way in the Norse sagas, where she tries to cougar it up with the decades-younger Harald Hardrada, at the time (1041) a twenty-something Viking prince in exile serving in the Varangian guard.
God Save Us from the Queen!: The Byzantine women were quite on par with the men, when it came to court intrigues. Possibly the most iconic case is Empress Theodora, an ex-"dancer" and the wife to Justinian I, considered to have had a notable impact on his policies. Some adaptations go as far as to make him Henpecked Husband. Then there was Empress Irene, whose reign was so reviled in the West, she might well be personally responsible for The Pope crowning Charlemagne as Emperor, as a "screw-you-Byzantines" gesture.
Irene's reputation was somewhat deserved, since she had her own son the Emperor Constantine VI blinded and usurped his throne. Yet she was apparently a good ruler, at least because she managed to end a long and destructive religious conflict, the iconoclast controversy (at least for a few decades).
To be more specific, what became known as Orthodox Christianity became the state religion of the Eastern Empire shortly after Constantine's death. By the Middle Ages, it had reached the point where it was intertwined with Byzantium itself.
In Name Only: This is the viewpoint of the Catholic world, as well as most modern Western historians. Byzantium's Western rivals were not inclined to consider it the legitimate heir of old Rome, but instead Imperium Graecorum, or Empire of the Greeks. Additionally, the ScandinavianVarangians described the country they served in as "Greece". Modern Western historians apply the term "Byzantine Empire," which was never used by the Byzantines themselves (they had always referred to themselves as the Roman Empire), to the Eastern Roman Empire after the fall of the Western Roman Empire in ~476. There are other conventions as to when exactly they should be considered "Byzantine" instead of "Roman," but referring to the "Roman Empire" past the 8th century is highly unusual.
The Arabs are a subversion, as the Arabic name for the Byzantines, was al-Rūm ("Rūm" is pronounced the way Americans say "room"), derived from "Roman".
Playing with Fire: The Byzantine Navy was well-equipped with flamethrowers firing a napalm-like substance called Greek Fire (in the West. The Byzantine called it Liquid Fire), that would burn even when soaked with water. Losing access to the areas that provided the components was a terrifying blow for the Empire, and the reason why the Fourth Crusade was successful instead that burned on sight.
At this point, it's worth noting that even during the glory days of The Roman Empire, the power of the Empire was always centered in the East due to the higher population, better fertility, and vastly greater urbanization and education among the peoples. In fact, historians generally agree that this is why the Eastern Roman Empire was able to survive the massive crises of the 3rd, 4th, and 5th centuries, while the Western Roman Empire imploded.
The Remnant: Even after Constantinople fell, a number of Byzantine remnants held out against the Ottomans for a few more decades, such as Mystras and Trebizond.
The Rival: To the Papacy and the Venetian Republic, as well as Sassanid Persia, the Abbasid and Umayyyad Caliphates, and ultimately the Ottoman Turks.
Serious Business: In the capital city, you could generally get a good riot going over two things: chariot races, and theology. The common folks took both of these very seriously (see the page quote).
The Theocracy: Even by the standards of medieval Christian societies, the line between the business of the state and of the church was an extremely thin one in Constantinople. Emperors had considerable say over ecclesiastical and theological matters, and religious disputes often had very significant political ramifications. There was a Patriarch who could and often did resist the Emperor's meddling in the church, and most Westerners overestimated how much power over the Church the Emperor had (which led to very real problems late in the game when the Pope demanded that the Byzantine Church unify with Rome in exchange for military aid from Catholic rulers, assuming that the Emperor could just order his people and church into compliance). Still, generally the Emperors enjoyed a religious authority most if not all Catholic rulers lacked or had to lock horns with the papacy for.
To Win Without Fighting: A large part of their strategy. They were more inclined toward chessmastery then straightforward fighting for the sensible reason that some other ruler would always fill the place of any they overthrew and any given rival might prove an ally some day.
Tragic Mistake: One could argue their chessmastery of gradually annexing all of the individual Armenian kingdoms in the 1000's directly led to their undoing; once having completely conquered Armenia and disbanded its armies (previously each individual region of Armenia had it's own militia protecting it, but this was made illegal under the Justinian reforms), replacing them with Byzantine draftees who had little to no incentive in defending Armenia, they might as well have left a welcome mat for the Turks who then easily invaded Anatolia, and a few hundred years later, took Constantinople. The Armenian kingdoms had been the cork keeping the Turkic tribes out of the area.
Interestingly, the original Europa Universalis 3 began the day after the empire fell in 1453. Then the expansions pushed this start date back to 1399 and the Empire became a playable minor faction. One which was rather popular and had lots of nation specific missions.
Similarly, history-based 4X and other Turn-Based Strategy games may have the Byzantines as a playable faction, as well. Civilization added the Byzantines in its third and fourth incarnations in their second expansion packs (Conquests and Beyond the Sword, respectively) under Theodora and Justinian, respectively. The Byzantines under Theodora were added to Civilization V with the first expansion pack, Gods & Kings.
The Belisarius Series features the Empire as the heroes of the series, fighting against the Big Bad's armies from the Malwa Empire.
In Axis Powers Hetalia, it's implied that Ancient Greece eventually became Byzantium, which takes then-Ottoman Turkey's role in ending the Empire a darker turn. This also could explain why her son Modern Greece bears a grudge against Turkey. Aside of being his prisoner after the fall of the empire itself.
Harry Turtledove studied Byzantine history at university, and as well as writing several stories (fantastic and mundane) set in the real thing, his Videssos fantasy series is based on a Fantasy Counterpart Culture version of the Empire and its neighbours.
The Kingdom of Gondor in The Lord of the Rings has some resemblances to the Byzantine Empire, being The Remnant of a once-great empire now in decline, and may have been partly inspired by it.