The Byzantine Empire was ruled by the Isaurian dynasty (or Syrian dynasty) from 717 to 802. The Isaurian emperors were successful in defending and consolidating the empire against the caliphates after the onslaught of the early Muslim conquests, but were less successful in Europe, where they suffered setbacks against the Bulgars, had to give up the Exarchate of Ravenna, and lost influence over Italy and the papacy to the growing power of the Franks.

The Isaurian dynasty is chiefly associated with Byzantine iconoclasm, an attempt to restore divine favour by purifying the Christian faith from excessive adoration of icons, which resulted in considerable internal turmoil. (Full article...)

The Byzantine Iconoclasm (Ancient Greek: Εἰκονομαχία, romanized: Eikonomachía, lit. 'image struggle', 'war on icons') were two periods in the history of the Byzantine Empire when the use of religious images or icons was opposed by religious and imperial authorities within the Ecumenical Patriarchate (at the time still comprising the Roman-Latin and the Eastern-Orthodox traditions) and the temporal imperial hierarchy. The First Iconoclasm, as it is sometimes called, occurred between about 726 and 787, while the Second Iconoclasm occurred between 814 and 842. According to the traditional view, Byzantine Iconoclasm was started by a ban on religious images promulgated by the Byzantine Emperor Leo III the Isaurian, and continued under his successors. It was accompanied by widespread destruction of religious images and persecution of supporters of the veneration of images. The Papacy remained firmly in support of the use of religious images throughout the period, and the whole episode widened the growing divergence between the Byzantine and Carolingian traditions in what was still a unified European Church, as well as facilitating the reduction or removal of Byzantine political control over parts of the Italian Peninsula.

Iconoclasm is the deliberate destruction within a culture of the culture's own religious images and other symbols or monuments, usually for religious or political motives. People who engage in or support iconoclasm are called iconoclasts, Greek for 'breakers of icons' (εἰκονοκλάσται), a term that has come to be applied figuratively to any person who breaks or disdains established dogmata or conventions. Conversely, people who revere or venerate religious images are derisively called "iconolaters" (εἰκονολάτρες). They are normally known as "iconodules" (εἰκονόδουλοι), or "iconophiles" (εἰκονόφιλοι). These terms were, however, not a part of the Byzantine debate over images. They have been brought into common usage by modern historians (from the seventeenth century) and their application to Byzantium increased considerably in the late twentieth century. The Byzantine term for the debate over religious imagery, iconomachy, means 'struggle over images' or 'image struggle'. Some sources also say that the Iconoclasts were against intercession to the saints and denied the usage of relics; however, it is disputed. (Full article...)

Greek Fire was an incendiary chemical weapon with spraying jet devices used by the Eastern Roman Empire (later known / renamed later by historians as the Byzantine Empire), with the imperial capital having moved from its longtime center in Rome in the A.D. 330s to the then Greek ancient (small but strategic) port town of Byzantium, on the Bosporus strait between the Black Sea to the north, and the Aegean / Mediterranean Seas to the south, and between continents of Europe to the west and Asia across the strait to the east. The growing mercantile city, of now increasing political / cultural and religious importance. (especially after later renamed Constantinople after the great reforming emperor Constantine the Great. It was he who moved the Empire from pagan religious beliefs to officially recognizing / adopting Christianity as a state religion. Here the divided but still huge Eastern Empire reorganized, consolidated and defended itself from northern, northeastern Germanic barbarian semi-civilized pagan tribes that had harassed, attacked and invaded into the Western Empire, occupying large segments and dividing it, breaking down the economic trade and cultural institutions in the then Western World. So Rome's legacy in Constantinople endured another thousand years, with the general language spoken being Greek although some remnants of Latin remained. However the people themselves in the East still referred to themselves and of their Empire as "Romans', and it endured until A. D. 1453, with the rising Muslim of the Ottoman Turks finally overwhelming the longtime fortified political / cultural capital of Constantinople, - later renamed Istanbul almost five centuries later in the 1920s.

With their long continuity of Greco-Roman civilization with its knowledge, culture and technology of science, architecture and engineering built up and passed down from the previous several thousand years in the Southeastern Europe, Mediterranean, North Africa, and Middle East regions in subsequent centuries. (Full article...)

Byzantine art comprises the body of artistic products of the Eastern Roman Empire, as well as the nations and states that inherited culturally from the empire. Though the empire itself emerged from the decline of western Rome and lasted until the Fall of Constantinople in 1453, the start date of the Byzantine period is rather clearer in art history than in political history, if still imprecise. Many Eastern Orthodox states in Eastern Europe, as well as to some degree the Islamic states of the eastern Mediterranean, preserved many aspects of the empire's culture and art for centuries afterward.

A number of contemporary states with the Eastern Roman (Byzantine) Empire were culturally influenced by it without actually being part of it (the "Byzantine commonwealth"). These included Kievan Rus', as well as some non-Orthodox states like the Republic of Venice, which separated from the Byzantine Empire in the 10th century, and the Kingdom of Sicily, which had close ties to the Byzantine Empire and had also been a Byzantine territory until the 10th century with a large Greek-speaking population persisting into the 12th century. Other states having a Byzantine artistic tradition, had oscillated throughout the Middle Ages between being part of the Byzantine Empire and having periods of independence, such as Serbia and Bulgaria. After the fall of the Byzantine capital of Constantinople in 1453, art produced by Eastern Orthodox Christians living in the Ottoman Empire was often called "post-Byzantine." Certain artistic traditions that originated in the Byzantine Empire, particularly in regard to icon painting and church architecture, are maintained in Greece, Cyprus, Serbia, Bulgaria, Romania, Russia and other Eastern Orthodox countries to the present day. (Full article...)

The fall of Constantinople, also known as the conquest of Constantinople, was the capture of the capital of the Byzantine Empire by the Ottoman Empire. The city was captured on 29 May 1453 as part of the culmination of a 53-day siege which had begun on 6 April.

The attacking Ottoman Army, which significantly outnumbered Constantinople's defenders, was commanded by the 21-year-old Sultan Mehmed II (later nicknamed "the Conqueror"), while the Byzantine army was led by Emperor Constantine XI Palaiologos. After conquering the city, Mehmed II made Constantinople the new Ottoman capital, replacing Adrianople. (Full article...)

The Nea Ekklēsia (Medieval Greek: Νέα Ἐκκλησία, "New Church"; known in English as "The Nea") was a church built by Byzantine Emperor Basil I the Macedonian in Constantinople between 876 and 880. It was the first monumental church built in the Byzantine capital after the Hagia Sophia in the 6th century, and marks the beginning of the middle period of Byzantine architecture. It continued in use until the Palaiologan period. Used as a gunpowder magazine by the Ottomans, the building was destroyed in 1490 after being struck by lightning. No traces of it survive, and information about it derives from historical accounts and depictions. (Full article...)

Byzantine currency, money used in the Eastern Roman Empire after the fall of the West, consisted of mainly two types of coins: gold solidi and hyperpyra and a variety of clearly valued bronze coins. By the 15th century, the currency was issued only in debased silver stavrata and minor copper coins with no gold issue.

The Byzantine Empire established and operated several mints throughout its history. Aside from the main metropolitan mint in the capital, Constantinople, a varying number of provincial mints were also established in other urban centres, especially during the 6th century. Most provincial mints except for Syracuse were closed or lost to invasions by the mid-7th century. After the loss of Syracuse in 878, Constantinople became the sole mint for gold and silver coinage until the late 11th century, when major provincial mints began to re-appear. Many mints, both imperial and, as the Byzantine world fragmented, belonging to autonomous local rulers, were operated in the 12th to 14th centuries. Constantinople and Trebizond, the seat of the independent Empire of Trebizond (1204–1461), survived until their conquest by the Ottoman Turks in the mid-15th century. (Full article...)

Byzantine music (Greek: Βυζαντινή μουσική) originally consisted of the songs and hymns composed for the courtly and religious ceremonial of the Byzantine Empire and continued, after the fall of Constantinople in 1453, in the traditions of the sung Byzantine chant of Eastern Orthodox liturgy. The ecclesiastical forms of Byzantine music are the best known forms today, because different Orthodox traditions still identify with the heritage of Byzantine music, when their cantors sing monodic chant out of the traditional chant books such as the Sticherarion, which in fact consisted of five books, and the Irmologion.

Byzantine music did not disappear after the fall of Constantinople. Its traditions continued under the Patriarch of Constantinople, who after the Ottoman conquest in 1453 was granted administrative responsibilities over all Eastern Orthodox Christians in the Ottoman Empire. During the decline of the Ottoman Empire in the 19th century, burgeoning splinter nations in the Balkans declared autonomy or autocephaly from the Patriarchate of Constantinople. The new self-declared patriarchates were independent nations defined by their religion. (Full article...)

The Fourth Crusade (1202–1204) was a Latin Christian armed expedition called by Pope Innocent III. The stated intent of the expedition was to recapture the Muslim-controlled city of Jerusalem, by first defeating the powerful Egyptian Ayyubid Sultanate. However, a sequence of economic and political events culminated in the Crusader army's 1202 siege of Zara and the 1204 sack of Constantinople, rather than the conquest of Egypt as originally planned. This led to the Partitio terrarum imperii Romaniae or the partition of the Byzantine Empire by the Crusaders and their Venetian allies leading to a period known as Frankokratia, or "Rule of the Franks" in Greek.

The Republic of Venice contracted with the Crusader leaders to build a dedicated fleet to transport their invasion force. However, the leaders greatly overestimated the number of soldiers who would embark from Venice, since many sailed from other ports, and the army that appeared could not pay the contracted price. In lieu of payment, the Venetian Doge Enrico Dandolo proposed that the Crusaders back him in attacking the rebellious city of Zadar (Zara) on the eastern Adriatic coast. This led in November 1202 to the siege and sack of Zara, the first attack against a Catholic city by a Catholic Crusader army, despite Pope Innocent III's calls for the Crusaders not to attack fellow Christians. The city was then brought under Venetian control. When the Pope heard of this, he temporarily excommunicated the Crusader army. (Full article...)

The Empire of Thessalonica is a historiographic term used by some modern scholars to refer to the short-lived Byzantine Greek state centred on the city of Thessalonica between 1224 and 1246 (sensu stricto until 1242) and ruled by the Komnenodoukas dynasty of Epirus. At the time of its establishment, the Empire of Thessalonica, under the capable Theodore Komnenos Doukas, rivaled the Empire of Nicaea and the Second Bulgarian Empire as the strongest state in the region, and aspired to capturing Constantinople, putting an end to the Latin Empire, and restoring the Byzantine Empire that had been extinguished in 1204.

Thessalonica's ascendancy was brief, ending with the disastrous Battle of Klokotnitsa against Bulgaria in 1230, where Theodore Komnenos Doukas was captured. Reduced to a Bulgarian vassal, Theodore's brother and successor Manuel Komnenos Doukas was unable to prevent the loss of most of his brother's conquests in Macedonia and Thrace, while the original nucleus of the state, Epirus, broke free under Michael II Komnenos Doukas. Theodore recovered Thessalonica in 1237, installing his son John Komnenos Doukas, and after him Demetrios Angelos Doukas, as rulers of the city, while Manuel, with Nicaean support, seized Thessaly. The rulers of Thessalonica bore the imperial title from 1225/7 until 1242, when they were forced to renounce it and recognize the suzerainty of the rival Empire of Nicaea. The Komnenodoukai continued to rule as Despots of Thessalonica for four more years after that, but in 1246 the city was annexed by Nicaea. (Full article...)

The Eastern Orthodox Church, officially the Orthodox Catholic Church, and also called the Greek Orthodox Church or simply the Orthodox Church, is the second-largest Christian church, with approximately 220 million baptised members. It operates as a communion of autocephalous churches, each governed by its bishops via local synods. The church has no central doctrinal or governmental authority analogous to the head of the Catholic Church (the pope). Nevertheless, the Ecumenical Patriarch of Constantinople is recognised by them as primus inter pares ("first among equals"), a title formerly given to the patriarch of Rome. As one of the oldest surviving religious institutions in the world, the Eastern Orthodox Church has played an especially prominent role in the history and culture of Eastern and Southeastern Europe.

Eastern Orthodox theology is based on the Scriptures and holy tradition, which incorporates the dogmatic decrees of the seven ecumenical councils, and the teaching of the Church Fathers. The church teaches that it is the one, holy, catholic and apostolic church established by Jesus Christ in his Great Commission, and that its bishops are the successors of Christ's apostles. It maintains that it practises the original Christian faith, as passed down by holy tradition. Its patriarchates, descending from the pentarchy, and other autocephalous and autonomous churches, reflect a variety of hierarchical organisation. It recognises seven major sacraments, of which the Eucharist is the principal one, celebrated liturgically in synaxis. The church teaches that through consecration invoked by a priest, the sacrificial bread and wine become the body and blood of Christ. The Virgin Mary is venerated in the Eastern Orthodox Church as the God-bearer and honoured in devotions. (Full article...)

The Muslim conquest of Sicily began in June 827 and lasted until 902, when the last major Byzantine stronghold on the island, Taormina, fell. Isolated fortresses remained in Byzantine hands until 965, but the island was henceforth under Muslim rule until conquered in turn by the Normans in the 11th century.

Although Sicily had been raided by the Muslims since the mid-7th century, these raids did not threaten Byzantine control over the island, which remained a largely peaceful backwater. The opportunity for the Aghlabid emirs of Ifriqiya came in 827, when the commander of the island's fleet, Euphemius, rose in revolt against the Byzantine Emperor Michael II. Defeated by loyalist forces and driven from the island, Euphemius sought the aid of the Aghlabids. The latter regarded this as an opportunity for expansion and for diverting the energies of their own fractious military establishment and alleviating the criticism of the Islamic scholars by championing jihad, and dispatched an army to aid him. Following the Arab landing on the island, Euphemius was quickly sidelined. An initial assault on the island's capital, Syracuse, failed, but the Muslims were able to weather the subsequent Byzantine counter-attack and hold on to a few fortresses. With the aid of reinforcements from Ifriqiya and al-Andalus, in 831 they took Palermo, which became the capital of the new Muslim province. (Full article...)

Byzantine architecture is the architecture of the Byzantine Empire, or Eastern Roman Empire, usually dated from 330 AD, when Constantine the Great established a new Roman capital in Byzantium, which became Constantinople, until the fall of the Byzantine Empire in 1453. There was initially no hard line between the Byzantine and Roman Empires, and early Byzantine architecture is stylistically and structurally indistinguishable from late Roman architecture. The style continued to be based on arches, vaults and domes, often on a large scale. Wall mosaics with gold backgrounds became standard for the grandest buildings, with frescos a cheaper alternative.

The richest interiors were finished with thin plates of marble or coloured and patterned stone. Some of the columns were also made of marble. Other widely used materials were bricks and stone. Mosaics made of stone or glass tesserae were also elements of interior architecture. Precious wood furniture, like beds, chairs, stools, tables, bookshelves and silver or golden cups with beautiful reliefs, decorated Byzantine interiors. (Full article...)

The East–West Schism, also known as the Great Schism or Schism of 1054, is the ongoing lack of communion between the Roman Catholic and Eastern Orthodox churches since 1054. It is estimated that, immediately following the beginning of the schism, a slim majority of Christians worldwide were Eastern Christians; most of the rest were Western Christians. A series of ecclesiastical differences and theological disputes between the Greek East and Latin West preceded the formal split that occurred in 1054. Prominent among these were the procession of the Holy Spirit (Filioque), whether leavened or unleavened bread should be used in the Eucharist, the Pope's claim to universal jurisdiction, and the place of the See of Constantinople in relation to the pentarchy.

The first action that would lead to a formal schism was taken in 1053: The Greek churches in southern Italy were required to conform to Latin practices, under threat of closure. In retaliation, Patriarch Michael I Cerularius of Constantinople ordered the closure of all Latin churches in Constantinople. In 1054, the papal legate sent by Leo IX travelled to Constantinople in order, among other things, to deny Cerularius the title of "ecumenical patriarch" and insist that he recognize the pope's claim to be the head of all of the churches. The main purposes of the papal legation were to seek help from the Byzantine emperor, Constantine IX Monomachos, in view of the Norman conquest of southern Italy, and to respond to Leo of Ohrid's attacks on the use of unleavened bread and other Western customs, attacks that had the support of Cerularius. The historian Axel Bayer says that the legation was sent in response to two letters, one from the emperor seeking help to organize a joint military campaign by the eastern and western empires against the Normans, and the other from Cerularius. When the leader of the legation, Cardinal Humbert of Silva Candida, O.S.B., learned that Cerularius had refused to accept the demand, he excommunicated him, and in response Cerularius excommunicated Humbert and the other legates. According to Ware, "Even after 1054 friendly relations between East and West continued. The two parts of Christendom were not yet conscious of a great gulf of separation between them. ... The dispute remained something of which ordinary Christians in East and West were largely unaware". (Full article...)

The Byzantine Empire was ruled by emperors of the dynasty of Heraclius between 610 and 711. The Heraclians presided over a period of cataclysmic events that were a watershed in the history of the Empire and the world. Heraclius, the founder of his dynasty, was of Armenian and Cappadocian (Greek) origin. At the beginning of the dynasty, the Empire's culture was still essentially Ancient Roman, dominating the Mediterranean and harbouring a prosperous Late Antique urban civilization. This world was shattered by successive invasions, which resulted in extensive territorial losses, financial collapse and plagues that depopulated the cities, while religious controversies and rebellions further weakened the Empire.

By the dynasty's end, the Empire had been transformed into a different state structure: now known in historiography as medieval Byzantine rather than (Ancient) Roman, a chiefly agrarian, military-dominated society that was engaged in a lengthy struggle with the Muslim Rashidun Caliphate and successor Umayyad Caliphate. However, the Empire during this period became also far more homogeneous, being reduced to its mostly Greek-speaking and firmly Chalcedonian core territories, which enabled it to weather these storms and enter a period of stability under the successor Isaurian dynasty. (Full article...)

The Despotate of Epirus (Medieval Greek: Δεσποτᾶτον τῆς Ἠπείρου) was one of the Greek successor states of the Byzantine Empire established in the aftermath of the Fourth Crusade in 1204 by a branch of the Angelos dynasty. It claimed to be the legitimate successor of the Byzantine Empire, along with the Empire of Nicaea and the Empire of Trebizond, its rulers briefly proclaiming themselves as Emperors in 1227–1242 (during which it is most often called the Empire of Thessalonica). The term "Despotate of Epirus" is, like "Byzantine Empire" itself, a modern historiographic convention and not a name in use at the time.

The Despotate was centred on the region of Epirus, encompassing also Albania and the western portion of Greek Macedonia and also included Thessaly and western Greece as far south as Nafpaktos. Through a policy of aggressive expansion under Theodore Komnenos Doukas the Despotate of Epirus also briefly came to incorporate central Macedonia, with the establishment of the Empire of Thessalonica in 1224, and Thrace as far east as Didymoteicho and Adrianople, and was on the verge of recapturing Constantinople and restoring the Byzantine Empire before the Battle of Klokotnitsa in 1230 where he was defeated by the Bulgarian Empire. After that, the Epirote state contracted to its core in Epirus and Thessaly, and was forced into vassalage to other regional powers. It nevertheless managed to retain its autonomy until being conquered by the restored Palaiologan Byzantine Empire in ca. 1337. In the 1410s, the Count palatine of Cephalonia and Zakynthos Carlo I Tocco managed to reunite the core of the Epirote state, but his successors gradually lost it to the advancing Ottoman Empire, with the last stronghold, Vonitsa, falling to the Ottomans in 1479. (Full article...)

The sack of Amorium by the Abbasid Caliphate in mid-August 838 was one of the major events in the long history of the Arab–Byzantine Wars. The Abbasid campaign was led personally by the Caliph al-Mu'tasim (r. 833–842), in retaliation to a virtually unopposed expedition launched by the Byzantine emperor Theophilos (r. 829–842) into the Caliphate's borderlands the previous year. Mu'tasim targeted Amorium, an Eastern Roman city in western Asia Minor, because it was the birthplace of the ruling Byzantine dynasty and, at the time, one of Byzantium's largest and most important cities. The caliph gathered an exceptionally large army, which he divided in two parts, which invaded from the northeast and the south. The northeastern army defeated the Byzantine forces under Theophilos at Anzen, allowing the Abbasids to penetrate deep into Byzantine Asia Minor and converge upon Ancyra, which they found abandoned. After sacking the city, they turned south to Amorium, where they arrived on 1 August. Faced with intrigues at Constantinople and the rebellion of the large Khurramite contingent of his army, Theophilos was unable to aid the city.

Amorium was strongly fortified and garrisoned, but a local inhabitant revealed a weak spot in the wall, where the Abbasids concentrated their attack, effecting a breach. Unable to break through the besieging army, Boiditzes, the commander of the breached section privately attempted to negotiate with the Caliph without notifying his superiors. He concluded a local truce and left his post, which allowed the Arabs to take advantage, enter the city, and capture it. Amorium was systematically destroyed, never to recover its former prosperity. Many of its inhabitants were slaughtered, and the remainder driven off as slaves. Most of the survivors were released after a truce in 841, but prominent officials were taken to the caliph's capital of Samarra and executed years later after refusing to convert to Islam, becoming known as the 42 Martyrs of Amorium. (Full article...)

Byzantine medicine encompasses the common medical practices of the Byzantine Empire from c. 400 AD to 1453 AD. Byzantine medicine was notable for building upon the knowledge base developed by its Greco-Roman predecessors. In preserving medical practices from antiquity, Byzantine medicine influenced Islamic medicine and fostered the Western rebirth of medicine during the Renaissance.

Byzantine physicians often compiled and standardized medical knowledge into textbooks. Their records tended to include both diagnostic explanations and technical drawings. The Medical Compendium in Seven Books, written by the leading physician Paul of Aegina, survived as a particularly thorough source of medical knowledge. This compendium, written in the late seventh century, remained in use as a standard textbook for the following 800 years. This tradition of compilation continued from around the tenth century into the twentieth through the genre of medical writings known as iatrosophia. (Full article...)

The Byzantine–Ottoman wars were a series of decisive conflicts between the Byzantine Greeks and Ottoman Turks and their allies that led to the final destruction of the Byzantine Empire and the rise of the Ottoman Empire. The Byzantines, already having been in a weak state even before the partitioning of their Empire following the 4th Crusade, failed to recover fully under the rule of the Palaiologos dynasty. Thus, the Byzantines faced increasingly disastrous defeats at the hands of the Ottomans. Ultimately, they lost Constantinople in 1453, formally ending the conflicts (however, several lasted until 1479).

Taking advantage of the situation, the Seljuk Sultanate of Rum began seizing territory in western Anatolia, until the Nicaean Empire was able to repulse the Seljuk Turks from the remaining territories still under Byzantine rule. Eventually Constantinople was re-taken from the Latin Empire in 1261 by the Nicaean Empire. The position of the Byzantine Empire in Europe remained uncertain due to the presence of the rivals in Epirus, Serbia and Bulgaria. This, combined with the declining power of the Sultanate of Rum (Byzantium's chief rival in Asia Minor) led to the removal of troops from Anatolia to maintain Byzantium's grip on Thrace. (Full article...)

The Byzantine Empire was ruled by emperors of the Komnenos dynasty for a period of 104 years, from 1081 to about 1185. The Komnenian (also spelled Comnenian) period comprises the reigns of five emperors, Alexios I, John II, Manuel I, Alexios II and Andronikos I. It was a period of sustained, though ultimately incomplete, restoration of the military, territorial, economic and political position of the Byzantine Empire.

Byzantium under the Komnenoi played a key role in the history of the Crusades in the Holy Land, while also exerting enormous cultural and political influence in Europe, the Near East, and the lands around the Mediterranean Sea. The Komnenian emperors, particularly John and Manuel, exerted great influence over the Crusader states of Outremer, whilst Alexios I played a key role in the course of the First Crusade, which he helped bring about. (Full article...)

The Byzantine navy was the naval force of the Byzantine Empire. Like the state it served, it was a direct continuation from its Roman predecessor, but played a far greater role in the defence and survival of the state than its earlier iteration. While the fleets of the Roman Empire faced few great naval threats, operating as a policing force vastly inferior in power and prestige to the army, command of the sea became vital to the very existence of the Byzantine state, which several historians have called a "maritime empire".

The first threat to Roman hegemony in the Mediterranean Sea was posed by the Vandals in the 5th century, but their threat was ended by the wars of Justinian I in the 6th century. The re-establishment of a permanently maintained fleet and the introduction of the dromon galley in the same period also marks the point when the Byzantine navy began departing from its late Roman roots and developing its own characteristic identity. This process would be furthered with the onset of the early Muslim conquests in the 7th century. Following the loss of the Levant and later Africa, the Mediterranean was transformed from a "Roman lake" into a battleground between the Byzantines and a series of Muslim states. In this struggle, the Byzantine fleets were critical, not only for the defence of the Empire's far-flung possessions around the Mediterranean basin, but also for repelling seaborne attacks against the imperial capital of Constantinople itself. Through the use of the newly invented "Greek fire", the Byzantine navy's best-known and feared secret weapon, Constantinople was saved from several sieges and numerous naval engagements resulted in Byzantine victories. (Full article...)

The Empire of Trebizond (Greek: Αυτοκρατορία της Τραπεζούντας), or Trapezuntine Empire, was a monarchy and one of three successor rump states of the Byzantine Empire, along with the Despotate of the Morea and the Principality of Theodoro, that flourished during the 13th through to the 15th century, consisting of the far northeastern corner of Anatolia (the Pontus) and portions of southern Crimea. The empire was formed in 1204 with the help of the Georgian queen Tamar after the Georgian expedition in Chaldia and Paphlagonia, commanded by Alexios Komnenos a few weeks before the sack of Constantinople. Alexios later declared himself Emperor and established himself in Trebizond (modern day Trabzon, Turkey). Alexios and David Komnenos, grandsons and last male descendants of deposed Emperor Andronikos I Komnenos, pressed their claims as "Roman emperors" against Byzantine Emperor Alexios V Doukas. The later Byzantine emperors, as well as Byzantine authors, such as George Pachymeres, Nicephorus Gregoras and to some extent Trapezuntines such as John Lazaropoulos and Basilios Bessarion, regarded the emperors of Trebizond as the "princes of the Lazes", while the possession of these "princes" was also called Lazica. Thus from the point of view of the Byzantine writers connected with the Laskaris and later with the Palaiologos dynasties, the rulers of Trebizond were not emperors.

After the crusaders of the Fourth Crusade overthrew Alexios V and established the Latin Empire, the Empire of Trebizond became one of three Byzantine successor states to claim the imperial throne, alongside the Empire of Nicaea under the Laskaris family and the Despotate of Epirus under a branch of the Angelos family. The ensuing wars saw the Empire of Thessalonica, the imperial government that sprang from Epirus, collapse following conflicts with Nicaea and Bulgaria and the final recapture of Constantinople by the Empire of Nicaea in 1261. Despite the Nicaean reconquest of Constantinople, the Emperors of Trebizond continued to style themselves as "Roman emperors" for two decades and continued to press their claim on the Imperial throne. Emperor John II of Trebizond officially gave up the Trapezuntine claim to the Roman imperial title and Constantinople itself 21 years after the Nicaeans recaptured the city, altering his imperial title from "Emperor and Autocrat of the Romans" to "Emperor and Autocrat of all the East, Iberia and Perateia". (Full article...)

The Byzantine Empire under the Macedonian dynasty underwent a revival during the late 9th, 10th, and early 11th centuries. Under the Macedonian emperors, the empire gained control over the Adriatic Sea, Southern Italy, and all of the territory of the Tsar Samuil of Bulgaria. The Macedonian dynasty was characterised by a cultural revival in spheres such as philosophy and the arts, and has been dubbed the "Golden Age" of Byzantium.

The cities of the empire expanded, and affluence spread across the provinces because of the newfound security. The population rose, and production increased, stimulating new demand for trade. (Full article...)

The Walls of Constantinople (Turkish: Konstantinopolis Surları; Greek: Τείχη της Κωνσταντινουπόλεως) are a series of defensive stone walls that have surrounded and protected the city of Constantinople (today Istanbul in Turkey) since its founding as the new capital of the Roman Empire by Theodosius II. With numerous additions and modifications during their history, they were the last great fortification system of antiquity, and one of the most complex and elaborate systems ever built.

Initially built by Constantine the Great, the walls surrounded the new city on all sides, protecting it against attack from both sea and land. As the city grew, the famous double line of the Theodosian Walls was built in the 5th century. Although the other sections of the walls were less elaborate, they were, when well-manned, almost impregnable for any medieval besieger. They saved the city, and the Byzantine Empire with it, during sieges by the Avar–Sassanian coalition, Arabs, Rus', and Bulgars, among others. The fortifications retained their usefulness after the advent of gunpowder siege cannons, which played a part in the city's fall to Ottoman forces in 1453 but were not able to breach its walls. (Full article...)

The Corpus Juris (or Iuris) Civilis ("Body of Civil Law") is the modern name for a collection of fundamental works in jurisprudence, issued from 529 to 534 by order of Byzantine Emperor Justinian I. It is also sometimes referred to metonymically after one of its parts, the Code of Justinian.

The work as planned had three parts: the Code (Codex) is a compilation, by selection and extraction, of imperial enactments to date; the Digest or Pandects (the Latin title contains both Digesta and Pandectae) is an encyclopedia composed of mostly brief extracts from the writings of Roman jurists; and the Institutes (Institutiones) is a student textbook, mainly introducing the Code, although it has important conceptual elements that are less developed in the Code or the Digest. All three parts, even the textbook, were given force of law. They were intended to be, together, the sole source of law; reference to any other source, including the original texts from which the Code and the Digest had been taken, was forbidden. Nonetheless, Justinian found himself having to enact further laws; today these are counted as a fourth part of the Corpus, the Novellae Constitutiones (Novels, literally New Laws). (Full article...)

John II Komnenos or Comnenus (Greek: Ἱωάννης ὁ Κομνηνός, romanized: Iōannēs ho Komnēnos; 13 September 1087 – 8 April 1143) was Byzantine emperor from 1118 to 1143. Also known as "John the Beautiful" or "John the Good" (Greek: Καλοϊωάννης, romanized: Kaloïōannēs), he was the eldest son of Emperor Alexios I Komnenos and Irene Doukaina and the second emperor to rule during the Komnenian restoration of the Byzantine Empire. As he was born to a reigning emperor, he had the status of a porphyrogennetos. John was a pious and dedicated monarch who was determined to undo the damage his empire had suffered following the Battle of Manzikert, half a century earlier.

John has been assessed as the greatest of the Komnenian emperors. This view became entrenched due to its espousal by George Ostrogorsky in his influential book, History of the Byzantine State, where John is described as a ruler who, "... combined clever prudence with purposeful energy ... and [was] high principled beyond his day." In the course of the quarter-century of his reign, John made alliances with the Holy Roman Empire in the west, decisively defeated the Pechenegs, Hungarians and Serbs in the Balkans, and personally led numerous campaigns against the Turks in Asia Minor. John's campaigns fundamentally changed the balance of power in the east, forcing the Turks onto the defensive; they also led to the recapture of many towns, fortresses and cities across the Anatolian peninsula. In the southeast, John extended Byzantine control from the Maeander in the west all the way to Cilicia and Tarsus in the east. In an effort to demonstrate the Byzantine ideal of the emperor's role as the leader of the Christian world, John marched into Muslim Syria at the head of the combined forces of Byzantium and the Crusader states; yet despite the great vigour with which he pressed the campaign, John's hopes were disappointed by the evasiveness of his Crusader allies and their reluctance to fight alongside his forces. (Full article...)

David Megas Komnenos (Greek: Δαυίδ Μέγας Κομνηνός, romanized: David Megas Komnēnos; c. 1408 – 1 November 1463) was the last Emperor of Trebizond from 1460 to 1461. He was the third son of Emperor Alexios IV of Trebizond and Theodora Kantakouzene. Following the fall of Trebizond to the Ottoman Empire, he was taken captive with his family to the Ottoman capital, Constantinople, where he and his sons and nephew were executed in 1463.

In July 2013, David and his sons and nephew were canonized by the Holy Synod of the Patriarchate of Constantinople. Their feast day was determined as 1 November, the anniversary of their deaths. (Full article...)

Theophanes the Confessor (Greek: Θεοφάνης Ὁμολογητής; c. 758/760 – 12 March 817/818) was a member of the Byzantine aristocracy who became a monk and chronicler. He served in the court of Emperor Leo IV the Khazar before taking up the religious life. Theophanes attended the Second Council of Nicaea in 787 and resisted the iconoclasm of Leo V the Armenian, for which he was imprisoned. He died shortly after his release.

Theophanes the Confessor, venerated on 12 March in both the Eastern Orthodox and the Roman Catholic churches, should not be confused with Theophanes of Nicaea, whose feast is commemorated on 11 October. (Full article...)

Gregory of Nazianzus (Greek: Γρηγόριος ὁ Ναζιανζηνός, romanized: Grēgorios ho Nazianzēnos; c. 329 – 25 January 390), also known as Gregory the Theologian or Gregory Nazianzen, was a 4th-century archbishop of Constantinople and theologian. He is widely considered the most accomplished rhetorical stylist of the patristic age. As a classically trained orator and philosopher, he infused Hellenism into the early church, establishing the paradigm of Byzantine theologians and church officials.

Gregory made a significant impact on the shape of Trinitarian theology among both Greek and Latin-speaking theologians, and he is remembered as the "Trinitarian Theologian". Much of his theological work continues to influence modern theologians, especially in regard to the relationship among the three Persons of the Trinity. Along with the brothers Basil the Great and Gregory of Nyssa, he is known as one of the Cappadocian Fathers. (Full article...)

George Amiroutzes (Pontic: Γεώργιος Ἀμιρούτζης; 1400–1470) was a Pontic Greek Renaissance scholar, philosopher and civil servant of the late Byzantine era. He was praised and respected for his outstanding knowledge, not only of theology and philosophy, but also of the natural sciences, medicine, rhetoric and poetry, all of which earned him the epithet the Philosopher (o Φιλόσοφος). He is a controversial figure due to his role in the fall of Trebizond and his later behavior as a servant of Sultan Mehmed II. (Full article...)

John Kourkouas (Greek: Ἰωάννης Κουρκούας, romanized: Ioannes Kourkouas, fl. c. 900–946), also transliterated as Kurkuas or Curcuas, was one of the most important generals of the Byzantine Empire. His success in battles against the Muslim states in the East reversed the course of the centuries-long Arab–Byzantine wars and set the stage for Byzantium's eastern conquests later in the century.

Kourkouas belonged to a family of Armenian descent that produced several notable Byzantine generals. As commander of an imperial bodyguard regiment, Kourkouas was among the chief supporters of Emperor Romanos I Lekapenos (r. 920–944) and facilitated the latter's rise to the throne. In 923, Kourkouas was appointed commander-in-chief of the Byzantine armies along the eastern frontier, facing the Abbasid Caliphate and the semi-autonomous Muslim border emirates. He kept this post for more than twenty years, overseeing decisive Byzantine military successes that altered the strategic balance in the region. (Full article...)

Alexios Apokaukos (Greek: Ἀλέξιος Ἀπόκαυκος; died 11 June 1345), also Latinized as Alexius Apocaucus, was a chief minister and head of the navy in the Byzantine Empire, during the reigns of emperors Andronikos III Palaiologos (r. 1328–1341) and John V Palaiologos (r. 1341–1357). Although he owed his rise to high state offices to the patronage of John VI Kantakouzenos (r. 1347–1354), he became, together with Patriarch John XIV Kalekas, one of the leaders of the faction supporting Emperor John V in the civil war of 1341–1347 against his one-time benefactor. Apokaukos died when he was lynched by political prisoners during an inspection of a new prison. (Full article...)

Nikephoros II Phokas (Νικηφόρος Φωκᾶς; c. 912 – 11 December 969), Latinized Nicephorus II Phocas, was Byzantine emperor from 963 to 969. His career, not uniformly successful in matters of statecraft or of war, nonetheless greatly contributed to the resurgence of the Byzantine Empire during the 10th century. In the east, Nikephoros completed the conquest of Cilicia and retook the islands of Crete and Cyprus, opening the path for subsequent Byzantine incursions reaching as far as Upper Mesopotamia and the Levant; these campaigns earned him the sobriquet "pale death of the Saracens". (Full article...)

Nikephoros Ouranos (Greek: Νικηφόρος Οὐρανός; fl. c. 980 – c. 1010), Latinized as Nicephorus Uranus, was a high-ranking Byzantine official and general during the reign of Emperor Basil II (r. 976–1025). One of the emperor's closest associates, he was active in Europe in the wars against the Bulgarians, scoring a major victory at Spercheios, and against the Arabs in Syria, where he held command during the first decade of the 11th century as Basil's virtual viceroy. A well-educated man, he wrote a military manual (Taktika) and composed several surviving poems and hagiographies. (Full article...)

Andronikos II Palaiologos (Greek: Ἀνδρόνικος Δούκας Ἄγγελος Κομνηνὸς Παλαιολόγος, romanized: Andrónikos Doúkās Ángelos Komnēnós Palaiologos; 25 March 1259 – 13 February 1332), Latinized as Andronicus II Palaeologus, reigned as Byzantine emperor from 1282 to 1328. His reign marked the beginning of the recently-restored empire's final decline. The Turks conquered most of Byzantium's remaining Anatolian territories, and Andronikos spent the last years of his reign fighting his own grandson in the First Palaiologan Civil War. The war ended in Andronikos' forced abdication in 1328, after which he retired to a monastery for the remainder of his life. (Full article...)

Procopius of Caesarea (Greek: Προκόπιος ὁ Καισαρεύς Prokópios ho Kaisareús; Latin: Procopius Caesariensis; c. 500 – 565) was a prominent late antique Greek scholar and historian from Caesarea Maritima. Accompanying the Roman general Belisarius in Emperor Justinian's wars, Procopius became the principal Roman historian of the 6th century, writing the History of the Wars, the Buildings, and the Secret History. (Full article...)

Manuel II Palaiologos or Palaeologus (Greek: Μανουὴλ Παλαιολόγος, romanized: Manouēl Palaiológos; 27 June 1350 – 21 July 1425) was Byzantine emperor from 1391 to 1425. Shortly before his death he was tonsured a monk and received the name Matthew. His wife Helena Dragaš saw to it that their sons, John VIII and Constantine XI, became emperors. He is commemorated by the Greek Orthodox Church on July 21. (Full article...)

Theodora (/ˌθiːəˈdɔːrə/; Greek: Θεοδώρα; c. 490 – 28 June 548) was a Byzantine empress and wife of emperor Justinian. She was from humble origins and became empress when her husband became emperor in 527 and was one of his chief advisers. Theodora is a saint in the Eastern Orthodox Church and the Oriental Orthodox Church, commemorated on 28 June. (Full article...)

Leo VI, called the Wise (Greek: Λέων ὁ Σοφός, romanized: Léōn ho Sophós, 19 September 866 – 11 May 912), was Byzantine Emperor from 886 to 912. The second ruler of the Macedonian dynasty (although his parentage is unclear), he was very well read, leading to his epithet. During his reign, the renaissance of letters, begun by his predecessor Basil I, continued; but the empire also saw several military defeats in the Balkans against Bulgaria and against the Arabs in Sicily and the Aegean. His reign also witnessed the formal discontinuation of several ancient Roman institutions, such as the separate office of Roman consul. (Full article...)

Theophilos (Greek: Θεόφιλος; sometimes Latinized or Anglicized as Theophilus or Theophilo; c. 812  – 20 January 842) was the Byzantine Emperor from 829 until his death in 842. He was the second emperor of the Amorian dynasty and the last emperor to support iconoclasm. Theophilos personally led the armies in his long war against the Arabs, beginning in 831. (Full article...)

Irene of Athens (Greek: Εἰρήνη, Eirḗnē; 750/756 – 9 August 803), surname Sarantapechaena (Greek: Σαρανταπήχαινα, Sarantapḗchaina), was Byzantine empress consort to Emperor Leo IV from 775 to 780, regent during the childhood of their son Constantine VI from 780 until 790, co-ruler from 792 until 797, and finally empress regnant and sole ruler of the Eastern Roman Empire from 797 to 802. A member of the politically prominent Sarantapechos family, she was selected as Leo IV's bride for unknown reasons in 768. Even though her husband was an iconoclast, she harbored iconophile sympathies. During her rule as regent, she called the Second Council of Nicaea in 787, which condemned iconoclasm as heretical and brought an end to the first iconoclast period (730–787). Her public figure was very polarizing during her 5 year reign, as most saw it as wrong for a woman to rule solely. Her reign as such made her the first ever empress regnant, ruling in her own right, in Roman and Byzantine imperial history.

The untimely death of her husband caused the throne to actually fall to her, leaving her solely in charge. During her regency with her son Constantine Irene became very influential in government policies. As Constantine reached maturity, he began to move out from under the influence of his mother. In the early 790s, several revolts tried to proclaim him as sole ruler. One of these revolts succeeded, but in 792 Irene was re-established in all imperial powers as co-emperor with Constantine. In 797, Irene organized a conspiracy in which her supporters gouged out her son's eyes, maiming him severely. He was imprisoned and probably died shortly afterwards. With him out of the way, Irene proclaimed herself sole ruler. Pope Leo III—already seeking to break links with the Byzantine East—used Irene's alleged unprecedented status as a female ruler of the Roman Empire to proclaim Charlemagne as Emperor of the Romans on Christmas Day of 800 under the pretext that a woman could not rule and so the throne of the Roman Empire was actually vacant. A revolt in 802 overthrew Irene and exiled her to the island of Lesbos, supplanting her on the throne with Nikephoros I. Irene died in exile less than a year later. (Full article...)

Theodosius I (Greek: Θεοδόσιος Theodosios; 11 January 347 – 17 January 395), also called Theodosius the Great, was a Roman emperor from 379 to 395. During his reign, he succeeded in a crucial war against the Goths, as well as in two civil wars, and was instrumental in establishing the creed of Nicaea as the orthodox doctrine for Christianity. Theodosius was the last emperor to rule the entire Roman Empire before its administration was permanently split between the West and East.

Born in Hispania, Theodosius was the son of a high-ranking general, Theodosius the Elder, under whose guidance he rose through the ranks of the Roman army. Theodosius held independent command in Moesia in 374, where he had some success against the invading Sarmatians. Not long afterwards, he was forced into retirement, and his father was executed under obscure circumstances. Theodosius soon regained his position following a series of intrigues and executions at Emperor Gratian's court. In 379, after the eastern Roman emperor Valens perished at the Battle of Adrianople against the Goths, Gratian appointed Theodosius as a successor with orders to take charge of the current military emergency. The new emperor's resources, and depleted armies, were not sufficient to drive the invaders out; in 382 the Goths were allowed to settle south of the Danube as autonomous allies of the empire. In 386, Theodosius signed a treaty with the Sasanian Empire which partitioned the long-disputed Kingdom of Armenia and secured a durable peace between the two powers. (Full article...)

Bardanes, nicknamed Tourkos, "the Turk" (Greek: Βαρδάνης ὁ Τοῦρκος, romanized: Bardanēs ho Tourkos, fl. 795–803), was a Byzantine general who launched an unsuccessful rebellion against Emperor Nikephoros I (r. 802–811) in 803. Although a major supporter of Byzantine empress Irene of Athens (r. 797–802), soon after her overthrow he was appointed by Nikephoros as commander-in-chief of the Anatolian armies. From this position, he launched a revolt in July 803, probably in opposition to Nikephoros's economic and religious policies. His troops marched towards Constantinople, but failed to win popular support. At this point, some of his major supporters deserted him and, reluctant to engage the loyalist forces in battle, Bardanes gave up and chose to surrender himself. He retired as a monk to a monastery he had founded. There he was blinded, possibly on Nikephoros's orders. (Full article...)

John I Doukas (Greek: Ἰωάννης Δούκας, romanized: Iōánnēs Doúkas), Latinized as Ducas, was an illegitimate son of Michael II Komnenos Doukas, Despot of Epirus in c. 1230–1268. After his father's death, he became ruler of Thessaly from c. 1268 to his own death in 1289. From his father's family he is also inaccurately known as John Angelos.

Married to a Thessalian Vlach woman, John first appears leading Vlach troops alongside his father in the lead-up to the Battle of Pelagonia in 1259. His defection to the camp of Emperor Michael VIII Palaiologos was crucial in the battle, which ended with the crushing defeat of the Epirotes' Latin allies and opened the way for the recovery of Constantinople and the re-establishment of the Byzantine Empire under Palaiologos in 1261. John quickly returned to the side of his father and brother, Nikephoros, and assisted them in recovering Epirus and Thessaly. After Michael II died, John Doukas became ruler of Thessaly with his seat at Neopatras, whence Western chroniclers often erroneously called him "Duke of Neopatras". (Full article...)

John VI Kantakouzenos or Cantacuzene (Greek: Ἰωάννης Ἄγγελος Παλαιολόγος Καντακουζηνός, Iōánnēs Ángelos Palaiológos Kantakouzēnós; Latin: Johannes Cantacuzenus; c. 1292 – 15 June 1383) was a Byzantine Greek nobleman, statesman, and general. He served as grand domestic under Andronikos III Palaiologos and regent for John V Palaiologos before reigning as Byzantine emperor in his own right from 1347 to 1354. Deposed by his former ward, he was forced to retire to a monastery under the name Joasaph Christodoulos (Greek: Ἰωάσαφ Χριστόδουλος) and spent the remainder of his life as a monk and historian. At age 90 or 91 at his death, he was the longest-lived of the Roman emperors. (Full article...)

Isaac I Komnenos or Comnenus (Greek: Ἰσαάκιος Κομνη­νός, Isaakios Komnēnos; c. 1007 – 1 June 1060) was Byzantine emperor from 1057 to 1059, the first reigning member of the Komnenian dynasty.

The son of the general Manuel Erotikos Komnenos, he was orphaned at an early age, and was raised under the care of Emperor Basil II. He made his name as a successful military commander, serving as commander-in-chief of the eastern armies between c. 1042 and 1054. In 1057 he became the head of a conspiracy of the dissatisfied eastern generals against the newly crowned Michael VI Bringas. Proclaimed emperor by his followers on 8 June 1057, he rallied sufficient military forces to defeat the loyalist army at the Battle of Hades. While Isaac was willing to accept a compromise solution by being appointed Michael's heir, a powerful faction in Constantinople, led by the ambitious Patriarch of Constantinople, Michael Keroularios, pressured Michael to abdicate. After Michael abdicated on 30 August 1057, Isaac was crowned emperor in the Hagia Sophia on 1 September. (Full article...)

Manuel the Armenian (Greek: Μανουήλ ὁ Ἀρμένιος), was a prominent Byzantine general of Armenian origin, active from c. 810 until his death. After reaching the highest military ranks, a palace conspiracy forced him to seek refuge in the Abbasid court in 829. He returned to Byzantine service the next year, receiving the position of Domestic of the Schools from Emperor Theophilos, who had married his niece Theodora. Manuel remained in the post throughout Theophilos's reign, and reportedly saved the emperor's life in the Battle of Anzen in 838. According to one report, he died on 27 July 838 of wounds received during the battle, but other sources record his survival past this date, ascribing him a major role in the regency that governed the empire after Theophilos's death, and report that he died some time around 860. (Full article...)

Anastasius I Dicorus (Greek: Ἀναστάσιος, translit. Anastásios; c. 431 – 9 July 518) was Eastern Roman emperor from 491 to 518. A career civil servant, he came to the throne at the age of 61 after being chosen by the wife of his predecessor, Zeno. His reign was characterised by reforms and improvements in the empire's government, finances, economy and bureaucracy. He is noted for leaving the empire with a stable government, reinvigorated monetary economy and a sizeable budget surplus, which allowed the empire to pursue more ambitious policies under his successors, most notably Justinian I. Since many of Anastasius' reforms proved long-lasting, his influence over the empire endured for many centuries.

Anastasius was a Miaphysite Christian and his personal religious tendencies caused tensions throughout his reign in the empire that was becoming increasingly divided along religious lines. He is venerated as a saint by the Syriac Orthodox Church on 29 July. (Full article...)

Michael II Komnenos Doukas, Latinized as Comnenus Ducas (Greek: Μιχαήλ Β΄ Κομνηνός Δούκας, Mikhaēl II Komnēnos Doukas), often called Michael Angelos in narrative sources, was from 1230 until his death in 1266/68 the ruler of the Despotate of Epirus, which included Epirus in northwestern Greece, the western part of Greek Macedonia and Thessaly, and western Greece as far south as Nafpaktos. (Full article...)

Alexios Doukas Philanthropenos (Greek: Ἀλέξιος Δούκας Φιλανθρωπηνός) was a Byzantine nobleman and notable general. A relative of the ruling Palaiologos dynasty, he was appointed commander-in-chief in Asia Minor in 1293 and for a time re-established the Byzantine position there, scoring some of the last Byzantine successes against the Turkish beyliks. In 1295 he rose up in revolt against Andronikos II Palaiologos, but was betrayed and blinded. Nothing is known of him until 1323, when he was pardoned by Andronikos II and sent again against the Turks, relieving a siege of Philadelphia, allegedly by his mere appearance. He was then named briefly governor of Lesbos in 1328, and again in 1336, when he recovered the island's capital from Latin occupation. He ruled the island thereafter, probably until his death in the 1340s. (Full article...)