Byzantium in the context of "Diptych"

Constantinople (see other names) was a historical city located on the Bosporus that served as the capital of the Roman (including its eastern continuation), Latin, and Ottoman empires between its consecration in 330 and the formal abolishment of the Ottoman sultanate in 1922. Initially, as New Rome, Constantinople was founded in 324 during the reign of Constantine the Great on the site of the existing settlement of Byzantium and in 330 became the capital of the Roman Empire. Following the collapse of the Western Roman Empire in the late 5th century, Constantinople remained the capital of the Eastern Roman Empire (also known as the Byzantine Empire; 330–1204 and 1261–1453), the Latin Empire (1204–1261), and the Ottoman Empire (1453–1922). In the aftermath of the Turkish War of Independence, the Turkish capital moved to Ankara. Although the city had been known as Istanbul since 1453, it was officially renamed Istanbul on 28 March 1930. As of October 2025, it is the most populous city in Europe, with a population of more than 16 million residents, straddling the Bosporus Strait and lying in both Europe and Asia, and is the financial center of Turkey.

In 324, following the reunification of the Eastern and Western Roman Empires, the ancient city of Byzantium was selected to serve as the new capital of the Roman Empire, and the city was renamed Nova Roma, or 'New Rome', by Emperor Constantine the Great. On 11 May 330, it was renamed Constantinople and dedicated to Constantine. Shortly afterward, in 474 AD, the Great Fire of Constantinople erupted and consequently devastated the region. Constantinople is generally considered to be the center and the "cradle of Orthodox Christian civilization." From the mid-5th century to the early 13th century, Constantinople was the largest and wealthiest city in Europe. The city became famous for its architectural masterpieces, such as Hagia Sophia, the cathedral of the Eastern Orthodox Church, which served as the seat of the Ecumenical Patriarchate; the sacred Imperial Palace, where the emperors lived; the Hippodrome; the Golden Gate of the Land Walls; and opulent aristocratic palaces. The University of Constantinople was founded in the 5th century and contained artistic and literary treasures before it was sacked in 1204 and 1453, including its vast Imperial Library. which contained more than 100,000 volumes. The city was the home of the Ecumenical Patriarch of Constantinople and guardian of Christendom's holiest relics, such as the Crown of Thorns and the True Cross.

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 Battle of Chaereonea was fought in 338 BC, near the city of Chaeronea in Boeotia, between Macedonia under Philip II and an alliance of city-states led by Athens and Thebes. The battle was the culmination of Philip's final campaigns in 339–338 BC and resulted in a decisive victory for the Macedonians and their allies.

Philip had brought peace to a war-torn Greece in 346 BC by ending the Third Sacred War and separately concluding his ten-year conflict with Athens for supremacy in the north Aegean with the Peace of Philocrates. Philip's much-expanded kingdom, powerful army and plentiful resources then made him the de facto leader of Greece. To many of the fiercely independent city-states, Philip's power after 346 BC was perceived as a threat, especially in Athens, where the politician Demosthenes led efforts to break away from Philip's influence. In 340 BC Demosthenes convinced the Athenian assembly to sanction action against Philip's territories and to ally with the Achaemenids in Byzantium, which Philip was besieging. These actions were against the terms of their treaty oaths and amounted to a declaration of war. In summer 339 BC, Philip therefore led his army towards South Greece, prompting the formation of an alliance of a few southern Greek states opposed to him, led by Athens and Thebes.

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.

The Second Athenian League was a maritime confederation of Greek city-states that existed from 378 to 355 BC under the leadership (hegemony) of Athens. It is sometimes referenced as the second Athenian Empire, despite operating as a confederation. The alliance represented a partial revival of the Delian League, which had been disbanded in 404 BC following the defeat of Athens in the Peloponnesian War. The new League was centered in the Aegean and included over 60 states, among which were Kos, Mytilene, Rhodes, and Byzantium. It was primarily formed as a defensive alliance against Sparta and secondly the Persian Empire. The new League's main objective was to preserve peace in Greece and counterbalance Sparta's growing hegemony and aggression. The League largely revived Athenian influence in the Greek world, reestablishing it as the strongest naval power in the eastern Mediterranean. This time, Athens made conscious efforts to avoid the strict terms that had eventually rendered the previous Delian League unpopular. The alliance lasted until 355 BC, when most of the allied cities became independent following the Social War that broke out in 357 BC.

Heraclea Lyncestis, also transliterated Herakleia Lynkestis (Ancient Greek: Ἡράκλεια Λυγκηστίς; Latin: Heraclea Lyncestis; Macedonian: Хераклеја Линкестис), was an ancient Greek city in Macedon, ruled later by the Romans. Its ruins are situated 2 km (1.2 mi) south of the present-day town of Bitola, North Macedonia. In the early Christian period, Heraclea was an important Episcopal seat and a waypoint on the Via Egnatia that once linked Byzantium with Rome through the Adriatic seaport of Dyrrachium. Some of its bishops are mentioned in synods in Serdica and other nearby towns. The city was gradually abandoned in the 6th century AD following an earthquake and Slavic invasions.

New Rome (Ancient Greek: Νέα Ῥώμη, Néa Rhṓmē; Koine Greek: [ˈne̞a ˈr̥o̞ːme̞ː]; Latin: Nova Roma; Late Latin: [ˈnɔwa ˈroma]) was the original name given by the Roman emperor Constantine the Great to his new imperial capital in 330 CE, which was built as an expansion of the city of Byzantium on the European coast of the Bosporus strait.

The city was founded as Byzantion (Ancient Greek: Βυζάντιον) by Megarian colonists in 657 BCE. It was renamed by Constantine the Great first as "New Rome" (Nova Roma) during the official dedication of the city as the new Roman capital in 330 CE, which he soon afterwards changed to Constantinople (Constantinopolis). The city was officially renamed as Istanbul in the 20th century, after the establishment of the Turkish Republic in 1923.

Neolithic artifacts, uncovered by archeologists at the beginning of the 21st century, indicate that Istanbul's historic peninsula was settled as far back as the 6th millennium BCE. That early settlement, important in the spread of the Neolithic Revolution from the Near East to Europe, lasted for almost a millennium before being inundated by rising water levels. The first human settlement on the Asian side, the Fikirtepe mound, is from the Copper Age period, with artifacts dating from 5500 to 3500 BCE. In the European side, near the point of the peninsula (Sarayburnu) there was a settlement during the early 1st millennium BCE. Modern authors have linked it to the possible Thracian toponym Lygos, mentioned by Pliny the Elder as an earlier name for the site of Byzantium.

There is evidence suggesting there were settlements around the region dating as far back as 6700 BC, and it is hard to define if there was any settlement on exact spot at city proper established, but earliest records about city proper begins around 660 BC when Greek settlers from the Attic town of Megara colonized the area and established Byzantium on the European side of the Bosphorus. It fell to the Roman Republic in 196 BC, and was known as Byzantium in Latin until 330, when the city, soon renamed as Constantinople, became the new capital of the Roman Empire. During the reign of Justinian I, the city rose to be the largest in the western world, with a population peaking at close to half a million people. Constantinople functioned as the capital of the Byzantine Empire, which effectively ended with the fall of Constantinople in 1453. Constantinople then became the capital of the Ottoman Turks.