Byzantium

Byzantium, originally Byzantion, was a Greek city founded in the 7th century BCE on the Bosporus at the site of present-day Istanbul. It controlled the strait linking the Black Sea with the Aegean and Mediterranean, making it a key hub of trade and military movement. In 330 CE the Roman Emperor Constantine the Great refounded it as Constantinople, the imperial capital, and it remained the eastern seat of empire for about a millennium. The name Byzantium is used by historians to refer to the later eastern realm and culture, though inhabitants often called the city New Rome.

As capital of the Eastern Roman or Byzantine Empire, the city preserved Greco-Roman traditions while developing a distinct Christian imperial state. It faced external pressure from Persians, Arabs, and later Turks, and internal tensions such as iconoclasm and the Great Schism. Notable episodes include the Theodosian Walls, the reign of Justinian I, the compilation of the Corpus Juris Civilis, and architectural achievements like Hagia Sophia. The administration used Greek as the language of law and culture, and the empire served as a major Christian center.

The Fourth Crusade sacked Constantinople in 1204, creating the Latin Empire until 1261 when the Byzantines restored control under the Palaiologos dynasty. The empire finally fell to the Ottoman Turks after the siege of 1453, marking the end of the Byzantine state. Its legacy includes the preservation of Roman law, Greek learning, Orthodox Christian tradition, and influences in art, architecture, and governance that shaped both Eastern and Western civilizations.