Constantinople in the context of Jacobus Angelus

Greeks or Hellenes (/ˈhɛliːnz/; Greek: Έλληνες, Éllines [ˈelines]) are an ethnic group and nation native to Greece, Cyprus, southern Albania, Anatolia, parts of Italy and Egypt, and to a lesser extent, other countries surrounding the Eastern Mediterranean and Black Sea. They also form a significant diaspora (omogenia), with many Greek communities established around the world.

Greek colonies and communities have been historically established on the shores of the Mediterranean Sea and Black Sea, but the Greek people themselves have always been centered on the Aegean and Ionian seas, where the Greek language has been spoken since the Bronze Age. Until the early 20th century, Greeks were distributed between the Greek peninsula, the western coast of Asia Minor, the Black Sea coast, Cappadocia in central Anatolia, Egypt, the Balkans, Cyprus, and Constantinople. Many of these regions coincided to a large extent with the borders of the Byzantine Empire of the late 11th century and the Eastern Mediterranean areas of ancient Greek colonization. The cultural centers of the Greeks have included Athens, Thessalonica, Alexandria, Smyrna, and Constantinople at various periods.

Thessaloniki (/ˌθɛsələˈniːki/; Greek: Θεσσαλονίκη [θesaloˈnici] ; also known by various spellings and names) is a city in northern Greece. The nation's second-largest, with slightly over one million inhabitants in its metropolitan area, it is the capital of the geographic region of Macedonia, the administrative region of Central Macedonia and the Decentralized Administration of Macedonia and Thrace. It is also known in Greek as i Symprotévousa, literally "the co-capital", a reference to its historical status as the "co-reigning" city (Symvasilévousa) of the Byzantine Empire alongside Constantinople.

Thessaloniki is located on the Thermaic Gulf, at the northwest corner of the Aegean Sea. It is bounded on the west by the delta of the Axios. The municipality of Thessaloniki, the historical centre, had a population of 319,045 in 2021, while the Thessaloniki metropolitan area had 1,006,112 inhabitants and the greater region had 1,092,919. It is Greece's second major economic, industrial, commercial and political centre, and a major transportation hub for Greece and southeastern Europe, notably through the Port of Thessaloniki. The city is renowned for its festivals, events and vibrant cultural life in general. Events such as the Thessaloniki International Fair and the Thessaloniki International Film Festival are held annually. Thessaloniki was the 2014 European Youth Capital. The city's main university, Aristotle University, is the largest in Greece and the Balkans.

The Byzantine Empire, also known as the Eastern Roman Empire, was the continuation of the Roman Empire centred on Constantinople during late antiquity and the Middle Ages. Having survived the events that caused the fall of the Western Roman Empire in the 5th century AD, it endured until the fall of Constantinople to the Ottoman Empire in 1453. The term 'Byzantine Empire' was coined only after its demise; its citizens used the term 'Roman Empire' and called themselves 'Romans'.

During the early centuries of the Roman Empire, the western provinces were Latinised, but the eastern parts kept their Hellenistic culture. Constantine I (r. 324–337) legalised Christianity and moved the capital to Constantinople. Theodosius I (r. 379–395) made Christianity the state religion and Greek gradually replaced Latin for official use. The empire adopted a defensive strategy and, throughout its remaining history, experienced recurring cycles of decline and recovery.

In modern historiography, the Western Roman Empire were the Roman Empire's western provinces, collectively, during any period in which they were administered separately from the eastern provinces by a separate, independent imperial court. Particularly during the period from AD 395 to 476, there were separate, coequal courts dividing the governance of the empire into the Western provinces and the Eastern provinces with a distinct imperial succession in the separate courts. The terms Western Roman Empire and Eastern Roman Empire were coined in modern times to describe political entities that were de facto independent; contemporary Romans did not consider the Empire to have been split into two empires but viewed it as a single polity governed by two imperial courts for administrative expediency. The Western Empire collapsed in 476, and the Western imperial court in Ravenna disappeared by 554, at the end of Justinian's Gothic War.

Though there were periods with more than one emperor ruling jointly before, the view that it was impossible for a single emperor to govern the entire Empire was institutionalized by emperor Diocletian following the disastrous civil wars and disintegrations of the Crisis of the Third Century. He introduced the system of the Tetrarchy in 286, with two senior emperors titled Augustus, one in the East and one in the West, each with an appointed subordinate and heir titled Caesar. Though the tetrarchic system would collapse in a matter of years, the East–West administrative division would endure in one form or another over the coming centuries. As such, the unofficial Western Roman Empire would exist intermittently in several periods between the 3rd and 5th centuries. Some emperors, such as Constantine I and Theodosius I, governed, if briefly, as the sole Augustus across the Roman Empire. On the death of Theodosius in 395, the empire was divided between his two infant sons, with Honorius as his successor in the West governing briefly from Mediolanum then from Ravenna, and Arcadius as his successor in the East governing from Constantinople.

Late antiquity is a period of time that comes after the end of classical antiquity and stretches into the beginning of the Early Middle Ages, though the exact start and end dates are debated. Late antiquity represents a cultural sphere covering much of the Mediterranean world, including parts of Europe and the Near East.

Late antiquity was an era of massive political and religious transformation. Religiously, it marked the origins or ascendance of the three major monotheistic religions: Christianity, rabbinic Judaism, and Islam, as well as the period when both the Bible and the Quran were canonized. Politically, it marked the ends of the Western Roman Empire and the Sasanian Empire (the last Persian empire of antiquity), as well as the beginning of the Arab conquests and the formation of the Rashidun Caliphate. Meanwhile, the Byzantine Empire became a militarized and Christianized society. Late antiquity was also an era of significant cultural innovation and transformation, marked by the emergence of public architecture like the Hagia Sophia, and the emergence of late antique literature and art.

Durrës (/ˈdʊrəs/ DUURR-əs, Albanian: [ˈdurəs]; Albanian definite form: Durrësi) is the second most populous city of the Republic of Albania and seat of Durrës County and Durrës Municipality. It is one of Albania's oldest continuously inhabited cities, with roughly 2,500 years of recorded history. It is located on a flat plain along the Albanian Adriatic Sea Coast between the mouths of the Erzen and Ishëm at the southeastern corner of the Adriatic Sea. Durrës's climate is profoundly influenced by a seasonal Mediterranean climate.

Durrës was founded under the name of Epidamnos around the 7th century BC, by ancient Greek colonists from Corinth and Corcyra in cooperation with the Taulantii, a local Illyrian tribe. Also known as Dyrrachium, Durrës developed as it became an integral part of the Roman Empire and its successor the Byzantine Empire. The Via Egnatia started in the city and led east across the fields, lowlands and highlands of the Balkan Peninsula to Constantinople.

Istanbul is the largest city in Turkey, constituting the country's economic, cultural, and historical heart. With a population over 15 million, it is home to 18% of the population of Turkey. Istanbul is among the largest cities in Europe and in the world by population. It is a city on two continents; about two-thirds of its population live in Europe and the rest in Asia. Istanbul straddles the Bosphorus—one of the world's busiest waterways—in northwestern Turkey, between the Sea of Marmara and the Black Sea. Its area of 5,461 square kilometers (2,109 sq mi) is coterminous with Istanbul Province. Under the Köppen climate classification, Istanbul's climate is considered a form of Mediterranean climate, with aspects of other temperate climate types.

The city now known as Istanbul developed to become one of the most significant cities in history. Byzantium was founded on the Sarayburnu promontory by Greek colonists, potentially in the seventh century BC. Over nearly 16 centuries following its reestablishment as Constantinople in 330 AD, it served as the capital of four empires: the Roman Empire (330–395), the Byzantine Empire (395–1204 and 1261–1453), the Latin Empire (1204–1261), and the Ottoman Empire (1453–1922). It was instrumental in the advancement of Christianity during Roman and Byzantine times, before the Ottomans conquered the city in 1453 and transformed it into an Islamic stronghold and the seat of the last caliphate. Although the Republic of Turkey established its capital in Ankara, palaces and imperial mosques still line Istanbul's hills as visible reminders of the city's previous central role. The historic centre of Istanbul is a UNESCO World Heritage Site.

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.

Edirne (US: /eɪˈdɪərnə, ɛˈ-/; Turkish: [e.ˈdiɾ.ne]), historically known as Orestias, Orestiada, Adrianople, or Adriana is a city in Turkey, in the northwestern part of the province of Edirne in Eastern Thrace. Situated 7 km (4.3 mi) from the Greek and 20 km (12 mi) from the Bulgarian borders, Edirne was the second capital city of the Ottoman Empire from the 1360s to 1453, before Constantinople became its capital.

The city is a commercial centre for woven textiles, silks, carpets and agricultural products and has a growing tourism industry. It is the seat of Edirne Province and Edirne District. Its population is 180,002 (2022).

Sophia, or Sofia (Koine Greek: σοφία, sophía—"wisdom") is a central idea in Hellenistic philosophy and religion, Platonism, and Gnosticism. Originally carrying a meaning of "cleverness, skill", the later meaning of the term, close to the meaning of phronesis ("wisdom, intelligence"), was significantly shaped by the term philosophía ("love of wisdom") as used by Plato.

In the Orthodox Church and the Catholic Church, the feminine personification of divine wisdom as Holy Wisdom (Ἁγία Σοφία; Hagía Sophía) can refer either to Jesus Christ the Word of God (as in the dedication of the church of Hagia Sophia in Constantinople) or to the Holy Spirit.

Constantine I (27 February 272 – 22 May 337), also known as Constantine the Great, or known mononymously as Constantine, was Roman emperor from AD 306 to 337 and the first Roman emperor to convert to Christianity. He played a pivotal role in elevating the status of Christianity in Rome, the Edict of Milan decriminalising Christian practice and ceasing Christian persecution. This was a turning point in the Christianisation of the Roman Empire. He founded the city of Constantinople (now Istanbul) and made it the capital of the Empire, which it remained for over a millennium.

Born in Naissus, a city located in the province of Moesia Superior (now Niš, Serbia), Constantine was the son of Flavius Constantius, a Roman army officer from Moesia Superior, who would become one of the four emperors of the Tetrarchy. His mother, Helena, was a woman of low birth, probably from Bithynia. Later canonised as a saint, she is credited for the conversion of her son in some traditions, though others believe that Constantine converted her. He served with distinction under emperors Diocletian and Galerius. He began his career by campaigning in the eastern provinces against the Persians, before being recalled to the west in AD 305 to fight with his father in the province of Britannia. After his father's death in 306, Constantine was proclaimed as augustus (emperor) by his army at Eboracum (York, England). He eventually emerged victorious in Civil wars of the Tetrarchy against the emperors Maxentius and Licinius to become the sole ruler of the Roman Empire by 324.

The Ecumenical Patriarchate of Constantinople (Greek: Οἰκουμενικὸν Πατριαρχεῖον Κωνσταντινουπόλεως, romanized: Oikoumenikón Patriarkhíon Konstantinoupóleos, IPA: [ikumeniˈkon patriarˈçion konstandinuˈpoleos]; Latin: Patriarchatus Oecumenicus Constantinopolitanus; Turkish: Rum Ortodoks Patrikhanesi, İstanbul Ekümenik Patrikhanesi, "Roman Orthodox Patriarchate, Ecumenical Patriarchate of Istanbul") is one of the fifteen to seventeen autocephalous churches that together compose the Eastern Orthodox Church. It is headed by the Ecumenical Patriarch of Constantinople.

Because of its historical location as the capital of the former Eastern Roman Empire and its role as the mother church of most modern Eastern Orthodox churches, Constantinople holds a special place of honor within Eastern Orthodox Christianity and serves as the seat for the Ecumenical Patriarch, who enjoys the status of primus inter pares (first among equals) among the world's Eastern Orthodox prelates and is regarded as the representative and spiritual leader of Eastern Orthodox Christians. Phanar (Turkish: Fener), the name of the neighbourhood where ecumenical patriarch resides, is often used as a metaphor or shorthand for the Ecumenical Patriarchate of Constantinople.

The Black Death was a bubonic plague pandemic that occurred in Europe from 1346 to 1353. It was one of the most fatal pandemics in human history; as many as 50 million people perished, perhaps 50% of Europe's 14th-century population. The disease is caused by the bacterium Yersinia pestis and spread by fleas and through the air. One of the most significant events in European history, the Black Death had far-reaching population, economic, and cultural impacts. It was the beginning of the second plague pandemic. The plague created religious, social and economic upheavals, with profound effects on the course of European history.

The origin of the Black Death is disputed. Genetic analysis suggests Yersinia pestis bacteria evolved approximately 7,000 years ago, at the beginning of the Neolithic, with flea-mediated strains emerging around 3,800 years ago during the late Bronze Age. The immediate territorial origins of the Black Death and its outbreak remain unclear, with some evidence pointing towards Central Asia, China, the Middle East, and Europe. The pandemic was reportedly first introduced to Europe during the siege of the Genoese trading port of Kaffa in Crimea by the Golden Horde army of Jani Beg in 1347. From Crimea, it was most likely carried by fleas living on the black rats that travelled on Genoese ships, spreading through the Mediterranean Basin and reaching North Africa, West Asia, and the rest of Europe via Constantinople, Sicily, and the Italian Peninsula. There is evidence that once it came ashore, the Black Death mainly spread from person-to-person as pneumonic plague, thus explaining the quick inland spread of the epidemic, which was faster than would be expected if the primary vector was rat fleas causing bubonic plague. In 2022, it was discovered that there was a sudden surge of deaths in what is today Kyrgyzstan from the Black Death in the late 1330s; when combined with genetic evidence, this implies that the initial spread may have pre-dated, by nearly two decades, the 14th-century Mongol conquests previously postulated as the cause.

Byzantine architecture is the architecture of the Byzantine Empire, or Eastern Roman Empire, usually dated from AD 330, 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 background 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.