Byzantine Empire, The
BYZANTINE EMPIRE, THE
The Byzantine Empire (Basileia ton Rhomaion ) is the scholarly designation of the section of the Roman Empire that survived in the eastern Mediterranean after the disappearance of Roman control in its western European provinces. It takes the name Byzantine from Byzantium, the name of the city founded as a colony of the ancient Greek city of Miletus. Emperor constantine i renamed the city constantinople for himself and rededicated it in respective ceremonies in 324 and on May 11, 330. Although institutional historians may date the commencement of the empire in a.d. 284, the Byzantines themselves usually looked back to 330. Legislation from the reign of Constantine I also framed their outlook on jurisprudence, because only occasionally did they look to earlier Roman precedents and jurisprudence of eras before Christian predominance within the empire. But Byzantine imperial symbols, institutions, bureaucracy, and visual culture all have their origins much earlier. The empire's formal name remained the Roman Empire, its head of state was the emperor of the Romans (Basileus ton Rhomaion ) and its subjects continued to call themselves Romans (Rhomaio ). No written constitution ever existed. In a vestigial sense, legitimacy remained with the senate and people. Gradually Roman law evolved into Byzantine law. Most, perhaps 80–90 percent of the empire's population, lived in the countryside from agricultural or pastoral occupations in any period of Byzantine history. Life expectancy was relatively short, infant mortality was high. There is no accurate estimate for the empire's total population, which probably peaked in the 6th century.
Periodization is imperfect, but traditionally historians often conveniently subdivide the history of the Byzantine Empire from a.d. 330 to 602, Early Byzantine Period; 610–1025 or 1081, Middle Byzantine Period; and 1025 to 1453, Late Byzantine. Older terminology that contrasted Later Roman with Eastern Roman periods (perhaps commencing the latter in a.d. 800 or 802) has become obsolete. These are modern historical constructions, not those of Byzantines, who often conceived time in stages beginning with the creation of the world, the reign of Augustus Caesar, the establishment of Constantinople under Constantine I, followed by respective imperial dynasties. Byzantine history is not merely an extension of ancient Greek or Roman or Western medieval history. It is a subject in its own right that deserves serious investigation without imposing criteria and frames of reference from other historical periods or regions. Yet it cannot be studied in complete isolation from other fields, with which it overlaps.
In the early period, the Byzantine Empire includes regions directly under the authority of the emperor at Constantinople, not that under his colleague at Rome or Ravenna. Hence in the early period before justinian i, its territories included Thrace, Moesia (Bulgaria), Asiatic Turkey, Syria, parts of Armenia, Jordan, Israel, Palestine, Egypt, and eastern Libya (Cyrenaica), Cyprus, islands in Aegean, and Crete. Justinian I will add Tripolitania, Tunisia, eastern Algeria, a strip of the southern Spanish coast from approximately the modern Portuguese-Spanish frontier to a point just below Valencia and the opposing northernmost tip of Morocco (Septem, or Ceuta), Sicily, Sardinia, Corsica, Italy, and the Dalmatian coast.
The Byzantine imperial archives do not survive. Only a few documents, such as laws, speeches, letters, and memoirs, however biased, remain. Byzantium was an empire that was conscious of and that used its history and the mystique of its history to maximize its prestige. It had a long memory. Its narrative historians emphasize political and military history from the perspective of Constantinople and imperial elites and often specific dynastic interests, not from the perspective of the majority of its subjects who have left us no narrative accounts of their own daily lives. We know the most about the 6th, 10th, 11th, and 14th centuries because of the quantities of written sources that have survived from these. There is nonliterary evidence. Lead seals provide a unique treasure of evidence in addition to inscriptions and coinage. Papyrology adds much new source material for the earliest period, up to the early 7th century, but mostly limited to
Egypt. Archaeology adds new material while its newer techniques and methodology are improving precision and raising and answering many questions.
Historical interpretation of the empire has changed in several ways. Testimonies of different historical sources are now better if still imperfectly understood. Historians, archaeologists, and art historians are now developing syntheses that take account of research in their respective specialities and those related to their own. We still need more synthesis and coordination between investigators of Late Antique and Middle Byzantine history. Historians no longer assume a monolithic and theocratic state for the Byzantine Empire. Much greater appreciation exists for the liveliness and bustling activities and changes that affected Byzantine society and culture than was the case a few decades ago. Religious controversies are not assumed to be simply expressions of social, political, ethnic, and economic interests, power, and advocacies: there may be genuine religious reasons for religious and theological disputes. More sensitivity exists for the difficulty of penetrating beneath the surface of Byzantine literary and historical texts and a greater understanding of the complexity of the codes and rules according to which they were written. More investigation is occurring for information about Byzantium in source materials from neighboring peoples, in Arabic, Syriac, Armenian, and Georgian as well as that in Latin and Greek. Muslim sources are providing much valuable information that was unknown and unappreciated for the 7th through 9th centuries. Newer techniques are being refined to utilize these sources more accurately while understanding the limits to which they can be put. Neglected questions about gender are receiving long overdue attention. Metallurgical analysis is beginning to provide more accurate information about Byzantine mining. More social and economic mobility existed in the early Byzantine period than scholars assumed.
Former interpretations of Byzantine history emphasized institutions as the key to explaining Byzantine history. A few decades ago the theme system was assumed to explain Middle Byzantine history and pronoia (temporary, then longer-term grant of revenues, usually from land) was the institutional fundamental device for explaining the Late Period. That is no longer the case, even though institutions are not irrelevant for a bureaucratic empire that lasted more than a millennium. Today historians do not assume that any single comprehensive social and economic reform of any single emperor created the Byzantine themes at one stroke. It is questionable how militarily efficient the thematic armies were at their height, whether they are the basic explanation for the survival of the Byzantine Empire against invasions by Muslim and Slavic and steppe invaders. Historians disagree concerning just how numerous and how efficient the Byzantine armies were at the end of the 6th century. Historians tend to assume that Byzantine field armies were relatively modest in size in the Middle Byzantine Period, that is, seldom more than 10 or 15 thousand soldiers. By the Palaeologan period Byzantium found it difficult to field armies of more than a few thousand troops. Historians no longer automatically assume that a highly centralized and regulated bureaucratic state was optimal for the Byzantine economy, society, and polity. Corporate regulation of the economy was a reality, but it is less clear that it was a blessing. More regional and municipal autonomy may have been desirable for prosperity, intellectual creativity, and political health. Historians no longer explain the dynamics of the 11th century internal history in terms of a dichotomy between a civil and military party; the reality was a far more complex domestic rivalry. Historians no longer simplistically posit a rivalry between European and Asiatic regions of the empire and they no longer consider the army to have been a monolith; familial, ethnic, and local bases created internal divisions.
The conversion of Constantine to Christianity (312) gave impetus to the Christianization of the empire. He and his court circle encouraged the creation of a rhetoric, art, and architecture of the Christian Roman Empire. He created a senate and consuls at Constantinople, to which he moved antiques. He created precedents for imperial relations with Christian church and inspired comparison of himself not only with earlier emperors but also with Moses. He summoned and participated in the Council of nicea, which settled issues of Trinitarian theology. But it was his son constantius ii (337–361) in whose reign the empire settled into an institutional routine at Constantinople. He normalized diplomatic relations with various neighboring peoples and embellished Constantinople. Missionary work spread Christianity north of the Danube and south into Ethiopia. War with Sasanian Persia attracted much imperial attention under Constantius II, tempted his successor julian (361–363) to a fatal and costly invasion of Persia. The outcome was humiliating defeat and the cession of valuable territory to the Persians. Julian's military debacle emboldened Christians and broke the hopes of most pagans for any restoration of their cults and privileges.
At some point in the 4th century after protracted imperial residence there the imperial bureaucracy established its norms and unwritten rules of conduct at Constantinople and began to transmit them to successors. Bureaucrats developed an understanding about the potential dynamics of power and procedures for administration from the perspective of the Golden Horn. Protocols developed for relations with imperial colleagues and their consuls and the other senate in Rome in the western Roman provinces. But controversies about the Holy Trinity rent the church and government until the definitive settlement by Emperor theodosius i in 381 at the Council of Constantinople. His legislation confirmed the unique status for orthodox Christianity and its clergy within the empire and the removal of wealth and privileges for pagan temples, cults, and their priests. Much pagan temple wealth had been confiscated and used for coinage as well as for embellishment and funding of Christian churches.
Many precedents for Byzantine ceremonies, rank, and hierarchy date to the 4th century. A gradual accretion of additional bits of ceremony occurred over the centuries. Competition for rank and office was important from the earliest Byzantine period until the end of the empire. Gradually elaborate ceremonies for a new emperor, for receiving credentials from an emperor in the west and other protocols took form and reached their ultimate recorded maturation in 10th-century documentation.
The empire's total budget or gross domestic product cannot be reliably estimated for any period. Principal treasuries in the earliest period were the Praetorian Prefecture, which assessed, collected and distributed tax revenue from land, the Count of the Sacred Largesses (mines, production, distribution of shirts to soldiers, recruitment taxes, and revenue from authenticating purity of precious metals), and the ires privata or Imperial Household, which administered very large accumulations of movable property as well as palaces, imperial estates, and their contents. Radical fiscal change occurred in the early 7th century, when these bureaus were reorganized and transformed. The Sacred Largesses disappeared. The Sakellarion Treasury evolved from the Praetorian Prefecture to become important in the 7th century. The Vestiarion became the imperial household's treasury, which handled the imperial family's movable and immovable wealth, in the broadest sense.
The empire lay astride the principal apertures and water corridors to the Mediterranean. Foremost was the complex of water passages of the Bosphorus and Dardanelles between the Aegean/Mediterranean and the Black Sea. It was essential for it to dominate these or face the danger of being split in half. Second was Egypt's narrow land corridor between the Mediterranean and the Red Sea, and third were the Straits of Gibraltar to the Atlantic. Both of these last two irrevocably slipped from Byzantine control by the death of Emperor Heraclius in 641. The empire's geopolitical situation made it difficult for it to wage simultaneous wars in the Balkans and in eastern Anatolia. It was difficult for it to project naval power into the Mediterranean further east than Sicily, Sardinia, or Tunisia. It wished to dominate the shores of the Black Sea but did not risk sending troops to seize the lands beyond the shores of the Black Sea. It was difficult for Byzantium to extend and maintain any effective political and military control northwest in Europe's interior beyond Belgrade.
A partial explanation for Byzantine survival lies in its ability to consult and use its accumulated hoard of ancient wisdom (Greek, Hellenistic, Roman, and earlier Byzantine) about diverse technological, geographical, political, military, and ethnological challenges. Historical contingencies also helped the empire to survive in the 5th century. In the 7th, 8th, and 9th centuries the empire profited from internal strife with the Umayyad and ’Abbasid Caliphates that it and its leaders had not conceived or created. It profited from, in much of its history, avoiding too much risky aggressive imperial overstretch. Its leaders' preference for cautious and prudent diplomacy with minimal risk of heavy casualties reduced the number of occasions in which everything was at stake in a single military expedition or battle. This reduced occasions in which ambitious military commanders or cliques or units could find opportunities to seize power or occasions in which the emperor might lose his life in combat or while on expedition. Yet prudent policies did not eliminate all conspiracies, for they were a fact of life in many centuries of the empire's history. Emperors and their advisers resorted to assassinations, and not infrequently at banquets or other moments when their opponents were caught off guard. The Byzantines preferred to use diplomacy, intrigue, and funds to persuade other peoples to wage war or exert pressure or engage in assassinations on its behalf instead of waging costly wars directly through calling up and dispatching its own troops.
The empire suffered some of its most enduring territorial losses during internal strife, in the 7th century (Levant and Egypt, North Africa), 9th century (Sicily), 11th century (most of Anatolia), late 13th (more western Anatolian regions), and 14th century (Aegean littoral and Gallipoli peninsula and Thrace).
The empire benefited from extensive trade beyond its frontiers in many directions in the early period, to Persia, Arabia, and the trans-Danubian regions, and to the central and western Mediterranean. Manufacture and export of ceramics, glass, and luxurious crafted small objects were prominent. Rare luxury items such as precious woods, fragrances, spices, condiments, and ivory were transported. Olive oil and wine were shipped in bulk. The volume of such items dropped sharply in the early 7th century. Statistics do not exist on the volume of trade or production of goods. Trade and handicrafts of commercial value contracted in towns and cities after the early 7th century but never completely disappeared. The economy quickened, especially in regions near the Aegean and Constantinople, in the 11th and 12th centuries although piracy took its toll in the 13th through 15th centuries. Anatolia and the Balkan regions both contained significant natural resources: ferrous and nonferrous metals, marble, and quarry stone. The agricultural economy's crops included grain, olive oil, wine, fruits, and nuts. The Balkans and Anatolia were suitable for raising livestock, including sheep, goats, oxen, and horses. The empire's seas yielded fish and shellfish, as well as salt that inhabitants extracted by evaporating seawater in salt pans. The empire sought some ships' timbers, furs, fragrances, amber, ivory, paper, and eunuchs from external sources.
After the contraction of its borders in the early 7th century the empire lacked navigable rivers. Maritime shipping was most efficient for bulk items. Land transportation was possible but slow, difficult, and relatively inefficient. Byzantium's economy benefited from being a crossroads for travel between Asia and Europe and between the Black Sea and Aegean and Mediterranean. Some ancient ports of Asia Minor silted up and other ports replaced them. The changed imperial borders still had their vulnerabilities. The Tauros and anti-Tauros mountain range marked southeastern limits, but no clear demarcation existed in the Balkans, despite the existence of the Rhodope and Balkan mountain ranges. Thessalonica became the empire's second largest city. Although Slavs and Avars threatened it, it did not fall to invaders until the destructive storming and looting of it by Arabs in 904, by Normans in 1185, and successive Crusader and Turkish seizures (1204, 1387, and 1430). Its inhabitants trusted to the protection of its patron St. demetrius. Slavic groups occupied much of mainland Greece in the 7th and 8th centuries but there is insufficient documentation to reconstruct a reliable narrative. Insecurity diminished but never extinguished international maritime traffic in the Mediterranean and Adriatic Seas.
By the 5th century the Byzantine bureaucracy was sufficiently strong that a weak sovereign would not dissolve the state. Germanic and other invasions over-whelmed the Roman government and its finances and military in the western provinces while the east survived. At least one minority constituency, pagans, did speak of the collapse of Roman government in the west using the verb "fall" (Damaskios, "fallen Rome") and hoped for its revival. Fifth-century imperial governments in the east attempted to help the west on several occasions but were usually unwilling to jeopardize their own existence in order to undertake risky military expeditions to the west that could cause civil war and rebellion. Byzantium succeeded in establishing internal security controls that prevented violent military seizures of power from becoming permanent. The price was restraint in international action. Governments learned to develop counterbalances to prevent any one single general or military or ethnic faction from becoming establishing a monopoly of military power.
The 4th century was one of rising population and economic prosperity for many cities and provinces in the east, in contrast to the instability and crises of the 3d century. The creation of new gold coinage the solidus (nomisma ), struck at 72 to the Roman pound, contributed to financial stability although there were winners and losers with a new money. Bronze coinage circulated most frequently for ordinary purposes. The gold coinage held its value and purity until the 11th century when debasement occurred rapidly over the course of a few decades. The Byzantine economy of the 11th century has received more positive reinterpretation as one with vibrant growth and expansion, not one of stagnation and decline. A reformed coinage stabilized the monetary situation from the late 11th to the end of the 12th century, after which Byzantine coinage increasingly yielded to more desirable Italian competing coins. By the early 15th century, the eastern Mediterranean merchants and people normally preferred Italian coins in transactions. Byzantium had difficulty, as had ancient states, in raising public loans or floating public debt; there was no adequate financial mechanism for doing so, except, at the end of the empire, for seeking embarrassing and risky loans from Italian commercial powers such as Venice.
By the middle of the 5th century the imperial government found it more prudent and expedient to pay off dangerous hostile barbarians such as the Huns instead of risking costly warfare with them. Despite criticism, the populace acquiesced. The imperial government with the aid of bureaucrats succeeded in preventing powerful generals from seizing and monopolizing power. Their efforts brought decisive results. Less successful was 5th-century imperial ecclesiastical policy. The Byzantine government and its provinces managed to hunker down to escape the most violent effects of the 5th-century barbarian invasions and settlements. Its diplomacy helped, but to some degree it enjoyed luck and also benefited from its location. There was strife on at least two occasions with Sassanian Persia, which Sassanian persecution of Armenian Christians exacerbated, but the borders remained essentially stable. The eastern provinces actually received some refugees from the west. Some pagan constituencies within it deplored the condition of "fallen Rome" (in their terms) and hoped for its restoration or revival late in the 5th century. Plagues cut population in the 6th century although the percentage drop and significance are controversial.
Constantinople grew rapidly. Its population probably peaked in the 6th century at approximately 400,000, which required the construction of greater walls in the early 5th century (Anthemian walls) as well as an aqueduct for more adequate water supply (reign of Valens, 364–378) for its people. The city's population enjoyed a grain dole at the expense of provincial Egypt. It was a city of excitement and activity that attracted many for entertainment and hopes of advancement. Constantinople was the scene, as were numerous other cities, of horse racing. Blue, green, red, and white factions existed there, in imitation of those at Rome, although eventually it was the blues and greens that predominated. Whether these had any political or social role has been the subject of modern scholarly dispute. Constantinopolitans appreciated and expected the appearance of their emperor and empress in scheduled public ceremonies, and grew anxious when their sovereigns absented themselves from the city.
Elsewhere in the empire Alexandria was the second largest city in the east, followed by Antioch. Western Asia Minor possessed extensive urban centers, most of which had a prosperous surrounding countryside. Egypt was a populous and rich but neglected province that emperors did not visit. Certain eastern provinces such as Palestine prospered from unprecedented new imperial generosity in support of new churches, facilities for the sick, and for pilgrims. Although a Christian empire, only Heraclius visited Jerusalem while emperor.
Ecclesiastical strife concerning Christology [see christology, controversies on (patristic)] and concerning episcopal ambitions consumed much governmental attention from the 430s on. Religious concerns were genuine in those disputes. They were not primarily vehicles of political, social, or economic pressure and protest and advocacy. But the decisions of the Council of Chalcedon in 451 made explicit definitions that led to a widening ecclesiastical cleavage that in retrospect would become permanent.
The privileges of Constantinople and its patriarch helped to make Constantinople into the de facto capital of the empire by the middle of the 5th century. Canon 28 of the Council of Chalcedon consolidated that authority. Some inhabitants of other principal eastern cities resented the rise of Constantinople to power, wealth, and prominence.
Justinian I and his advisers took advantage of vulnerabilities in several Germanic kingdoms in the west to reconquer Africa from the vandals, Italy from the Ostrogoths, albeit slowly, and started the never completed reconquest of Spain. These efforts brought early fame and treasures to the empire. They expended liberally to build churches and fortifications in the empire's newly liberated and old regions. But they soon overstretched imperial military and financial resources with harmful consequences for core areas of the empire, especially the Balkans, which lacked the soldiers to defend themselves from Avar attack and Slavic settlement. Byzantine military activity prompted the Persian king Chosroes I to embark on war with the Byzantines, which lasted much of the century. Justinian's conquests shifted the empire somewhat more to a more diversified population with an additional proportion of Latin-speaking population. His legislation and official rhetoric and some institutional arrangements consciously invoked an archaizing classical heritage.
lombard invasions of Italy, heightened Berber raids in Africa, and intensified Gothic resistance in the Iberian peninsula deprived Byzantium of many rewards for its military efforts and increased the tenuousness of its hold on those territories.
The pace of events and developments accelerated in the early 7th century. Violent usurpation of the imperial throne by Phocas in 602 gave the Sassanian king Chosroes II (590–628) the pretext to go to war against Byzantium for a quarter century starting in 603. The successful rebellion by heraclius overthrew Phocas in turn (608–610) but did not persuade Chosroes II, who was winning, to cease hostilities. Instead, his forces overran Byzantine upper Mesopotamia, Syria, Palestine, and Egypt and ravaged Asia Minor. Sassanian occupation gave the inhabitants of those lands experience of living outside of Byzantine authority. Byzantine forces evacuated their remaining territories in Spain. Only after extraordinary efforts and risking capture of Constantinople by a combined Persian and Avaro-Slav siege and blockade was Heraclius in a series of campaigns and by skillful exploitation of internal strife within Persia, able to crush Persia, overthrow Chosroes II, and impose peace terms acceptable to Byzantium. The lengthy war and aftermath involved considerable physical destruction and disruptive dislocation of populations. As it turned out, the empire had virtually no respite before new and different Muslim conquests took away the liberated territories from Byzantine control once more. Heraclius and his advisers miscalculated the Muslim threat, which constituted a different challenge from that of the Sassanian Persians. He was unable to devise techniques to divide and neutralize the Muslims. He had been an emperor who seized imperial power by means of skillful exploitation of internal strife and intrigues, and also used these methods even more than standard warfare to overcome the Persians. But he and his advisers could not find the means to bring about decisive blows against the Muslims even though he managed to extricate and spare sufficient Byzantine troops and territory such that a significant remnant of the empire could survive. Successive threats in the east prevented the government from giving attention to the deteriorating condition in the Balkans. The extensive luxury and classical literature and art and the supporting cultural infrastructure gradually disappeared with the attenuation of financial resources and urban structures.
Heraclius managed to return the captured fragment of the Cross to Jerusalem (March 630), to begin the difficult task of reconciling divided Christian churches under his favored but highly controversial Christological formula of monothelitism (one will in Jesus Christ). Harsh policies against Jews, including some instances of massacre and forced baptism, intensified Christian-Jewish strife and Jewish alienation during the reign of Heraclius in widely scattered areas of the empire: Palestine, Edessa and its region in north Syria, and in North Africa. But early in the 630s Muslims terminated Heraclius's efforts at reunification and reconstruction by invading and conquering Palestine and Syria and upper Mesopotamia. By the early 640s they also seized Egypt and then North Africa by the end of the 7th century. Their conquests resulted in enormous Byzantine losses of tax revenue, population, and resources and food and tremendous loss of prestige. The empire lost its richest and most populous and most urbanized regions, even though they included ethnically, linguistically, and religiously diverse populations. Byzantines failed to anticipate the Muslim invasions or the religious convictions that enabled these invaders to hold together.
Seventh-century military reverses compelled the empire to fall back on the security of Constantinople's walls and rely upon its territories and population and economy in Asia Minor as its heartland. Key political and military leaders and the best military units resided there. Most of southeastern Europe fell outside of the government's control. The land and maritime fortifications of Constantinople gave important protection, symbolism, and security. Many vestiges of late antique institutions, privileges, and practices disappeared.
Heraclius founded a dynasty, which historians call Heraclian, that endured tenuously until 711. A grave succession crisis at Heraclius's death in 641 exacerbated conditions. We know little about details in the reign of his grandson Constantius II (641–668), except for strong Muslim raids into Asia Minor and deeper Slavic penetration of the Balkans and the Greek mainland. Muslim raiders escalated their penetrations of Byzantine Anatolia in 662–663 by beginning to winter there, not merely engage in summer raids. Muslims blockaded and unsuccessfully besieged Constantinople between 674 and 678 during the reign of Constantine IV. Long-distance trade shrank. Monothelitism worsened the empire's relations with the Papacy and Italy. Constantine IV finally repudiated the dynasty's previous Monothelitic policies in 681.
One of the greatest puzzles in Byzantine historical investigation is explanation of the change from late antiquity to the middle period with respect to social and economic and landholding and military classes, including demography, as well as with respect to education, ethnicity, and trade and handicrafts. The paucity of primary sources contributes to obscurity. Many aspects of the continuity of Greek ethnic identity remain controversial and unexplained, but some continuing sense of Greek identity persisted. Older theses of ethnic disappearance are now obsolete and rejected.
Gradually, administrative boundaries were redrawn and reorganized within the empire during the late 7th and early 8th century, resulting in the incremental creation of military districts and their armies called "themes" (from Greek themata ). This resulted from no single emperor's action, although the first four (Anatolikon, Armeniakon, Opsikion, and Thrakesion) appeared by the end of the 660s. Their relationship, if any, with social and economic reforms is unproven. The administrative rank and function lists changed substantially by the 9th and early 10th centuries from those that had existed in the 4th through 6th centuries. The Praetorian Prefecture's treasury disappeared in the 7th century in place of the General Treasury (logothesion tou genikou ) and the Private Treasury (logothesion tou eidikou ), which are attested to by late in the 7th century. Warehouses for kommerkiarioi apparently emerge as part of a new logistical support for the reorganized military, but many technical details remain unexplained. The precise steps and causes are uncertain. The imperial authorities gradually subdivided the original four themes, perhaps to reduce the potential for military unrest as well for improvement of administrative efficiency, and added additional smaller units as territorial reconquest extended control over additional regions. The government relied more heavily on Armenian talent than it had in the early Byzantine period. The basis for the funding of soldiers altered significantly from that of the early Byzantine period: soldiers received cash pay less regularly and many gradually came to subsist off of lands where they were billeted. Armies withdrawn from Syria were stationed in various regions of Anatolia where they gradually identified themselves with localities. Towns survived but often in attenuated form, concentrated around citadels for security. The social elites that dominated towns in late antiquity disappeared or receded in the 7th and later centuries. New names appeared.
Heraclius's successors managed to check and restrain Muslim raiding of Asia Minor even though the raiders inflicted much damage on the economy, communications, and demographics of the region. Use of Greek fire, an igneous petroleum mixture, helped to thwart the Muslim blockade and siege of Constantinople between 674 and 678. But the arrival of Bulgars who settled just south of the Danube added another threat in southeastern Europe, one that the Byzantines failed to dislodge. The Bulgars and Slavs remained non-Christian until the late 9th century. But by the end of the 7th century the Byzantines had developed adequate techniques to fortify and check Muslim advances in Asia Minor. Byzantines only gradually recovered effective administrative control of parts of mainland Greece that Slavs had occupied. That process terminated by the beginning of the 10th century. It is impossible to ascertain the precise extent of Byzantine territorial control in the lower Balkans and Greek mainland during many decades of the 7th through 9th century and obscurities persist with respect to Byzantine administrative control in many parts of the northern and northwest Balkans even in the late 10th and early 11th century. The second Muslim (and last "Arab") siege of Constantinople failed in the years 717–718.
Apocalyptic fears intensified from the middle of the 7th to the early 8th century. Muslim victories against Byzantines and others shook Byzantine confidence and contributed to religious searching and doubts. They, in addition to the negative reactions of some ecclesiastics and laity against veneration of religious pictures of sacred persons and subjects, resulted in Byzantium's greatest internal trauma, the iconoclastic controversy (see icono clasm). It initially erupted at the end of the 720s and in 730 under Emperor Leo III, and intensified under his son Constantine V, peaking in the 760s. Its origins, nature, and significance remain controversial and inadequately documented. Only in the 750s did iconoclasm develop theological reasoning in favor of its policies. Constantine V found himself fighting strong monastic opposition, which continued to the bedrock of icon veneration through the termination of the crisis. The sources on iconoclasm are not ideal and tend to distort or obscure the motives of the iconoclasts, who have not left their own testimony for critical evaluation. Leo's daughter-in-law, Empress Irene, succeeded in reversing this dynastic policy in 787, with the aid of the Seventh Ecumenical Council that she convoked at Nicea, but more instability followed. Irene's strife with her son Constantine VI culminated in his blinding. But revulsion at his death resulted in Irene's overthrow, the end of the Syrian or Isaurian dynasty in 802, and a kaleidoscopic change of emperors until Leo V the Armenian restored iconoclasm (Second Iconoclastic Period) between 815 and 843. The abortive yet multifaceted revolt of Thomas the Slav at the beginning of the 820s was another symptom of instability. Finally Empress Theodora decisively restored veneration of icons (Triumph of Orthodoxy) on March 11, 843.
Iconoclasm contributed to the costly Byzantine loss of Italy, Sardinia, and Sicily due to local hostility to the policy and to imperial preoccupation with dealing with issues of iconoclasm. This reduced the proportion of Latin speakers to a very small minority within the empire. Muslims from North Africa also took advantage of Byzantine vulnerability in the central Mediterranean to expand and to seize Crete, thereby creating a base for piratical raiding against Byzantine shipping and coastlines.
Byzantine relations were initially difficult with the Frankish empire of Charlemagne, including concerning icon policy, which the emperor's advisers misunderstood. There were sensitivities concerning the issue of recognizing the imperial status of Charlemagne and his successors, but vulnerable Byzantines grudgingly conceded this during a crisis with the Bulgars in 812. The disastrous defeat and death of Emperor Nicephorus I at the hands of the Bulgar khan Krum in 811 was a great humiliation for Byzantium and precipitated a crisis of legitimacy and contributed to the restoration of iconoclasm.
Intellectual, economic, and political revival quickened in the 9th century. Trade intensified with Khazars (an Altaic people settled on the edge of and near the Black Sea and aperture of the Volga) and the Rus' (ancestors of the Russians). Other exchanges including diplomatic and intellectual and artistic dimensions accelerated with the ‘Abbāsids in Baghdad, after they supplanted the Umayyad dynasty and moved the seat of caliphal government from Syria to Iraq. After the early 840s, Muslim raids gradually tempered against Byzantine Asia Minor. The Byzantines developed a reasonably effective system for containing and neutralizing such raiders. Byzantine military victories extinguished a heretical Paulician (a Christian sect with putative dualist theological assumptions) buffer entity at Tephrike and prepared the way for more ambitious Byzantine recovery of lost territories in the southeast.
The seizure of power by Basil I "the Macedonian" led to the long-lived Macedonian dynasty that endured from 867 (a traditional threshold in periodization) until 1042, the longest-lived Byzantine dynasty with the exception of its last, the Palaeologans. During it the study and revision of law thrived, commerce expanded, while institutions gained new strength and imperial armies gradually recovered territories in the east from the Muslims.
Basil I's seizure of power brought in his wake a new group of leaders, who will together with their descendants benefit from the long life of this dynasty. Many of them will profit from imperial favor and patronage and will entrench themselves in key positions and even establish dominance of specific localities. These families will extend their prominence in the 10th century. Some, however, will harm themselves through their own excessive reach for power (for example, Phocas, Maleinos families). The principal families in the 10th century were the Lecapenos, Phocas, Tzimisces, Maleinos, Musele, Argyros, Rentakius, Parsacutenos, and Scleros families. Growing centralization made aristocratic families more dependent on the government. Yet the imperial government needed aristocratic families for officers. Rebellions of the Scleros (976, 987) and Phocas (987) families represented rejection of imperial authority by a large segment of Byzantine aristocratic families. Emperor Basil II (976–1025) heavily influenced which families dominated the 11th century. The Lecapenos, Phocas, and Maleinos families were eclipsed, while the Scleros family remained important. Basil II relied heavily on a transitional group of families: Argyros, Kourkouas, Bourtzes, Abalantes, Malakinos, Nikoulitzes. But Basil II created a group of newcomers to counterbalance and dispersed power among many families: Apokaukos, Boiannes, Botaneiates, Cabasilas, Comnenos, Dalassenos, Diogenes, Ducas, Gabras, Glabas, Kekaumenos, Monomachos, Pakourianos, Peognites, Tarchaniotes, Synadenos, Taronites, Tornikios, Vatatzes, Xiphias, among others. Basil II wished to restrain new men as well as break the power of the older families. He wished to make families dependent on him. He virtually liquidated the formerly powerful office of Domestic of the Schools (commander-in-chief of armies of Asia). After 996 the major families seem to have become weaker. New families lacked familial alliances and the group cohesion of the old families of the 10th century. Imperial central power remained in the ascendancy until 1057. Familial power was erratic in the middle of the 11th century, but reemerged after 1055. Chief families remained the same between 1057 and 1081, even though their mutual strife intensified in those years.
Imperial concerns for the accumulation of excessive power in the hands of large landowners culminated in the repeated issuance of legislation to check such fiscally and militarily harmful trends (such trends tended to threaten the tax base for agricultural taxes and threaten the supply of able-bodied soldiers for military service). Legislation speaks of the powerful and the poor and indicates that military obligations had become attached to the land by the 10th century. The earliest known legislation restricting or attempting to reverse expansionist tendencies occurred in 930 but peaked under Basil II in 996. With great difficulty and after civil war, Basil II succeeded in breaking the power of several truculent families, but the problem revived and worsened after his death in 1025. But imperial legislation did check and confine the magnates to the central Anatolian plateau; it was not a total failure. One of the great magnate leaders, Nicephorus II Phocas, reconquered the strategic and valuable islands of Crete and Cyprus and the north Syrian city of Antioch. These acts stimulated economic growth and maritime activity.
The Byzantine mission under Constantine and Methodius in 863 resulted in the conversion of south Slavs, in particular conversion of the Bulgar khan Boris and his subjects in 864 and the development of a Slavic alphabet and liturgy and translation of some basic Christian texts into Slavic. But Bulgarian weakness tempted Byzantine diplomacy to exploit the situation. Bulgaria fell under Byzantine control only to throw off Byzantine control under Tsar Samuel late in the 10th and early in the 11th century. Basil II after painful and ruthless efforts and much destructive warfare reduced Bulgaria to submission by 1018. Basil II's reign witnessed the creation of a strong alliance with the Rus', whose sovereign Vladimir dispatched troops to aid Basil II. A crack imperial guard unit of Varangians will continue to exist at Constantinople even into the impoverished 14th century.
Basil II also annexed Armenian and Georgian territories and continued the policies of Nicephorus II Phocas and John I Tzimisces in expanding eastward. He annexed lands that he did not have sufficient civilian or military populations with whom to assimilate to the body of the empire. Disaffected locals in many instances resented imposition of Byzantine authority from afar. Byzantine authority over occupied regions in Bulgaria and the edge of the Caucasus was superficial and vulnerable. These were cases of dangerous imperial overstretch even though strategic logic and the desire for more fiscal revenues underlay their acquisition.
The imperial government experienced a regency at the death of Leo VI in 911. His uncanonical fourth marriage created a crisis of legitimacy in and after his lifetime. His son and legal successor, the vulnerable, young Constantine VII, found himself under the protectorate of a military commander, romanus i lecapenus until a coup ousted the Lecapenids in 944. The Byzantines mastered international diplomacy in the middle of the 10th century to employ relatively low-cost leverage of steppe tribes such as the Pechenegs to coerce the Bulgars and other peoples to serve and respect Byzantine interests. Byzantine diplomacy reached its apogee in the middle of the 10th century. The extensive writings of and collected by Constantine VII reveal the accumulated strategic and antiquarian wisdom of the Byzantines and describe their imperial ceremonies and receptions at the moment of their greatest splendor.
Tensions between Greeks and Armenians within the Byzantine Empire divided Byzantines in the east in the middle and late 11th century, contemporary with the Seljuk Turkish invasions. Controversial is the question of conditions in eastern Anatolia on the eve of the Turkish invasions: density of population, state of the economy, ethnic and linguistic and confessional composition of the populace, and the policies for appointing and financing Byzantine officials and soldiers in those regions. Elucidation of the causes for the success of the Turkish invasions depends partially on assumptions about conditions prior to their arrival. The government did not succeed in moderating or eliminating these problems. Neglect and unraveling of older defense and muster systems together with civil war in the wake of the capture of Emperor Romanus IV Diogenes at the battle of Mantzikert in 1071 exposed Anatolia to Seljuk invasion. Within a decade the Byzantines had lost effective control of most of Anatolia. Also in 1071 Normans ejected the Byzantines from their remaining positions in southern Italy. At the end of the 11th century Byzantium found itself best by Turks in the east, by steppe raiders (Pechenegs, Cumans) to the northeast, and by Normans in the west, who threatened the Balkans from Bari and other ports in southern Italy. The imperial government resorted to more use of Latin (Frankish, Norman, Anglo-Saxon) mercenary troops as well as recruits from west Altaic peoples such as the Pechenegs and Cumans and increasingly even from eastern Turks.
alexius i comnenus (1081–1118) stabilized the military situation at a high price: he sought the assistance of Western military forces, who to his surprise transformed themselves into the First Crusade. Crusaders helped him recover some valuable territory and towns in Anatolia from the Seljuks, but misunderstandings and disagreements raised insoluble tensions with Crusaders who established principalities in the territories that they conquered in the Levant. He reformed coinage and the tax system, and prosecuted what some contemporaries regarded as excessively free inquiry in theology and philosophy. He established a dynasty that endured until 1185.
The crusades brought increased trade and more Westerners for residence at Constantinople. Byzantine resentments soared and culminated in riots and looting directed against Latins (Venetians, Genoese, Pisans) and their property and warehouses at Constantinople in 1171 and 1182. These acts exacerbated tensions and generated Italian claims for damages and reparations. Centrifugal forces increased, culminating in the successful rebellion of Bulgars under the Asenids in 1186 while other Crusaders seized the rich and strategic island of Cyprus.
Another crisis of legitimacy struck Byzantium at the end of the 12th century. Andronicus I Comnenos managed to rebel and seize power but Isaac I Angelus overthrew and executed him in 1185. But Alexius III Angelos overthrew and blinded Isaac and set in motion a disastrous chain of events that culminated in the Fourth Crusaders' seizure of Constantinople (April 13, 1204), which terminated the Angeli dynasty. On May 16, 1204, Crusaders elected Baldwin of Hainault as Latin emperor and a Venetian patriarch after looting and massacring in Constantinople. Theodore Lascaris and many other Constantinopolitans fled to the nearby Asian countryside while David Comnenus established an independent principality in Trebizond and Michael Angelos Ducas created a despotate (principality) in remote Epiros. The most important intellectuals and political refugees clustered at Nicea to rally around Theodore Lascaris and his patriarch. The Latins failed to win over the Greek population and were disastrously defeated by Bulgars. Resentment of Greeks and other Orthodox against Latins and against ecclesiastical reunion intensified because of the Fourth Crusade and experiences under Crusader occupation or other negative experiences with Latins with respect to trade, diplomacy, or cultural contact. Negative sentiments worsened and the list of perceived Latin theological and liturgical "errors" lengthened. With patient diplomacy and careful military movements, Byzantines ultimately recovered Constantinople in 1261 and ejected the Crusaders, even though Venetians continued to rule many rich islands in the Aegean and Ionian Seas, Genoese gained numerous strong points and lucrative trading posts, and other Crusaders held strong points in Attica and the Peloponnesus. Crusader occupation and intervention inflicted much material and human damage but also tied Greeks irrevocably to the broader Mediterranean world and its economic and political transformations. Byzantines after 1204 fell behind innovations in the West and the Islamic world. Their ships could not effectively compete with those of the Italian maritime powers in the profitable and important long-distance trade. A tightly knit group of families, foremost of which were the Palaeologi, controlled dwindling economic and political resources.
Issues of ecclesiastical reunion bedeviled relations with the West, especially after the schism of 1054. Emperors and their ministers at Nicea held out the hope of reunion of churches, but were unwilling to implement it fully. In July 1274, to forestall another Crusade by Charles of Anjou against Constantinople, Emperor Michael VIII Palaeologus's envoy, George Acropolites, agreed to reunion on behalf of the emperor and gave on his behalf a profession of faith. But this was unenforceable. Patriarch John Bekkos consented to reunion in 1275. But the church was already rent asunder by other disaffected factions angry with the deposition and blinding of Emperor John Lascaris by Michael Palaeologus. The death of Pope Gregory, the inability of Emperor Michael and Patriarch John Bekkos to implement union fully, and political pressures for another crusade to recover Constantinople led to papal excommunication of Emperor Michael VIII on Nov. 18, 1281, not long before his death. His successor Emperor Andronikos II (1282–1328) allowed union to lapse. Each party was sure of its own superiority, showed little respect for what it knew of the other, and was ready to condemn the slightest deviation from its own norms. Old issues remained, including acceptance of Roman primacy, the filioque, Canon 28 of the Council of Chalcedon, the use of unleavened bread in the Latin Eucharist, prohibited degrees of marriage, the status of the just and unjust immediately after decease, and other questions. There was mutual ignorance: a complete lack of understanding and sympathy. So union was not feasible at that time. Old ecclesiastical frictions continued at Byzantium. Hence the deposition and estrangement of the "Arsenite" faction that supported the ousted Patriarch Arsenios. But Arsenios's successor Patriarch Joseph was also ousted because of his rejection of reunion. These factions did not reconcile themselves until 1312.
By the second decade of the 14th century plans for new crusades against Byzantium gave way to realization of the seriousness of the Turkish peril. The emergence of various Turkish beyliks on the former Byzantine lands in Asia Minor was a partial result of local dissatisfaction with Palaeologan overthrow of the locally popular Lascaris family. By the 2d and 3d decade of the 14th century Michael VIII's son Andronicus II and his advisers had permanently lost control of all but a few posts in Asia Minor, with grave fiscal and strategic consequences. Efforts to secure Western military assistance backfired because of the Byzantine inability to pay the mercenaries and ethnic tensions. Treacherous massacre of Catalan commanders and their bodyguards prompted remaining Catalans to retaliate by looting and ravaging the countryside and population between Thrace and Attica. They eventually seized control of Athens and the surrounding region from 1311 until 1388.
Civil war between andronicus ii and his grandson Andronicus IV worsened conditions, even though intellectuals such as Nicephorus Choumnos and Theodore Metochites managed to pursue their philosophical investigations and debates. John VI Cantacuzenus took advantage of the young John V Paleologus and his mother Anna of Savoy to seize power. hesychasm divided Byzantines as well until its adherents triumphed by 1341. John VI supported gregory palamas and his hesychast faction and theology and mysticism. Palamism assumed a distinctly anti-Latin tone. Meanwhile plague (Black Death 1347–48) killed many, with grave demographic and economic repercussions. The Turkish occupation of the strategic town of Gallipoli on the Gallipoli peninsula in 1354 prompted the abdication of John VI Cantacuzenus, who retired to a monastery. The Serb tsar Stefan Dushan temporarily threatened to occupy and supplant Byzantium, especially in northern Greece, claiming (1346) to be emperor of the Serbs and Greeks, but his premature death in 1355 terminated Serbia's thrust for Balkan supremacy. Ottoman occupation spread rapidly in Europe in the face of inadequate Byzantine resistance or failed coordination of defenses with other Balkan nationalities. Ottoman victories over Serbs and Crusaders in the Balkans in 1371, 1389, and 1396 confirmed Byzantine weakness. Since 1371 or 1373 Byzantium had in effect been a client of the burgeoning Ottoman empire. Although Western efforts to assist a beleaguered Byzantium were irregular and insufficient in size and scope and financing, Byzantine internal strife had crippled the empire's ability to develop any effective defensive strategy.
Emperor John V (1341–91) unsuccessfully sought aid in Italy while Manuel II visited Italy, France, and England in search of relief forces. John V experienced humiliating treatment in Italy due to Byzantium's poor credit rating. Timur's unexpected victory over Ottoman sultan Bayezid I in 1402 provided a respite to Byzantium, probably enabling the empire to survive another half-century. Towns and countryside and coastlines and monasteries suffered from depredations of plague, pirates, and land raiders during the 14th and early 15th centuries.
Byzantine leaders resorted to resourceful diplomacy, but failed to devise institutional, technological, tactical, or other innovations to enable them to resist the Ottomans successfully or compete economically and culturally with the Italian trading cities. John VIII Palaeologus (1425–48) and his brother Constantine XI (1448–53) negotiated desperately for Western assistance. John VIII agreed to reunion at the Council of Ferrara-Florence in 1439 but was unable to persuade many antiunionist clergy and laity to follow his lead. The failure of the Crusade of Varna in 1444 was the last serious hope for Western relief for the Byzantine Empire. The Ottoman sultan Muḥammad II resolved to seize Constantinople, which he accomplished by its storming on May 29, 1453, in the course of which Emperor Constantine XI died in the breach of the walls. By that time the population of Constantinople had probably fallen to 50,000 or less. The modest but intellectually vigorous despotate of the Morea (Peloponnesus) continued to remain independent under Thomas and Demetrius Palaeologus, brothers of Constantine XI, until the Ottomans overran it in 1460. The empire at Trebizond fell to Muḥammad II in 1461. Thomas Palaeologus and his family fled to Italy where their titles to Byzantine imperial rights became the object of future international claims.
The final decades of the empire require study in a larger context, for the empire's dimensions had shrunk to the size of an ancient polis. Italian humanist interest in Greek language, manuscripts, and antiquities grew and took advantage of ecclesiastical diplomacy concerning union of the churches to improve communications and contacts with individual Byzantine scholars, and in a few cases to learn something about monuments and physical antiquities.
Investigation of the Byzantine Empire is not at an end. Many historical topics still need more analysis: the Byzantine village; the Byzantine diet; Byzantium and Russia; eunuchs; mortuary practices; death and memory; Byzantine spirituality in the late 10th and early 11th centuries, including relationships with military elites and monasticism; Byzantine court ceremonial; Arabic sources on the late 7th, 8th, and 9th centuries require more exploitation; comparative analysis of Byzantine and Western European economic and technological activity, especially in the 10th and early 11th centuries; the monastery; Byzantium and the Later Crusades; and consciousness of any ethnic identity, still need a basic study. Many questions remain concerning familial alliances. The late 5th century, the late 10th and early 11th centuries, Justinian I and his legislation, Byzantine Sicily, and land tenure in Anatolia in the 4th through 6th centuries need a major review. Byzantine patristic works deserve much more intensive analysis. Many Byzantine literary, historical, and epigraphic sources still await the preparation and publication of rigorous critical editions, translations, and commentaries. These inquiries, and others that we cannot yet imagine, should amplify but also transform the historical interpretation of the history of the Byzantine Empire.
Bibliography: There is no optimal and up-to-date single-volume history of the Byzantine Empire. m. angold, Byzantine Empire 1025–1204 (2d ed. New York 1997); A Byzantine Government in Exile: Government and Society under the Laskarids of Nicea 1204–1261 (Oxford 1975). m. bartusis, The Late Byzantine Army (Philadelphia 1992). a. bellinger and p. grierson, eds., Catalogue of the Byzantine Coins in the Dumbarton Oaks Collection and the Whittemore Collection, 5 v. (Washington, D.C. 1966–99). c. m. brand, Byzantium Confronts the West (Cambridge, Mass.1968). a. cameron, ed., The Cambridge Ancient History (rev. ed. Cambridge, England 2000–) v. 13–14. g. cavallo, ed., The Byzantines (Chicago 1997). j.-c. cheynet, Pouvoir et Contestation à Byzance (963–1210) (Paris 1990). g. dagron, Naissance d'une Capitale (Paris 1974). j. v. fine jr., The Early Medieval Balkans (Ann Arbor, Mich. 1983); The Late Medieval Balkans (Ann Arbor, Mich. 1987). j. gill, Byzantium and the Papacy, 1198–1400 (New Brunswick, N.J. 1979). j. haldon, Warfare, State and Society in Byzantium 565–1204 (London 1999). m. hendy, Studies in the Byzantine Monetary Economy (Cambridge 1985). r. janin, Constantinople Byzantine (Paris 1964). a. h. m. jones, The Later Roman Empire (Oxford 1964). w. kaegi, Byzantine Military Unrest 471–843: An Interpretation (Amsterdam 1981); Byzantium and the Decline of Rome (Princeton 1968); Byzantium and the Early Islamic Conquests (Cambridge 1995). a. kazhdan, Oxford Dictionary of Byzantium, 3 v. (Oxford 1991). t. m. kolbaba, The Byzantine Lists: Errors of the Latins (Urbana, Ill. 2000). a. laiou, Peasant Society in the Late Byzantine Empire (Princeton 1977). a. laiou and d. simon, eds., Law and Society in Byzantium, Ninth–Twelfth Centuries (Washington, D.C. 1994). a. laiou et al., Economic History of Byzantium, 3 vols. (Washington 2002). p. magdalino, The Empire of Manuel I Komnenos (Cambridge 1996); ed., The Rhythm of Imperial Renewal in Byzantium, 4th–13th Centuries (Brookfield, Vt. 1994). c. mango, Byzantium and Its Image (London 1984); Byzantium: The Empire of New Rome (New York 1980). r. morris, Monks and Laymen in Byzantium (Cambridge 1995). j. nesbitt and n. oikonomides, eds., Byzantine Seals in Dumbarton Oaks and in the Fogg Museum of Art, 4 v. (Washington, D.C. 1991–2001). d.m. nicol, Last Centuries of Byzantium (2d ed. Cambridge 1994). g. ostrogorsky, History of the Byzantine State, tr. j. hussey (Oxford and New Brunswick, N.J. 1968). Out of date. e. patlagean, Pauvrete économique et pauvreté sociale à Byzance, 4e–7e siècles (Paris 1977). e. stein, Histoire du Bas-Empire, 2 v. (Paris 1949,1959). p. stephenson, Byzantium's Balkan Frontier (Cambridge 2001). a.-m. talbot, ed., Byzantine Defenders of Images (Washington, D.C. 1998); Holy Women of Byzantium (Washington, D.C.1996). j. thomas, a. c. hero, and r. allison, eds. and trs., Byzantine Monastic Foundation Documents, 5 v. (Washington, D.C.2000). w. treadgold, The Byzantine Revival (Stanford 1984). s. vryonis, The Decline of Medieval Hellenism in Asia Minor (Berkeley, Los Angeles 1971).
[w. e. kaegi]
"Byzantine Empire, The." New Catholic Encyclopedia. . Encyclopedia.com. (August 15, 2018). http://www.encyclopedia.com/religion/encyclopedias-almanacs-transcripts-and-maps/byzantine-empire
"Byzantine Empire, The." New Catholic Encyclopedia. . Retrieved August 15, 2018 from Encyclopedia.com: http://www.encyclopedia.com/religion/encyclopedias-almanacs-transcripts-and-maps/byzantine-empire