Byzantium was founded by Byzas who landed on the promontory on the European side of the Aegean Sea when he sailed from Greece toward the Black Sea. On the opposite shore was the city of Chalcedon and Byzas wondered why Chalcedon was founded there instead on the more defensible promontory just a half-mile away. A more colorful narrative is that Byzas had consulted the Oracle at Delphi to ask where to make his new city and the oracle told him to find it opposite the blind. Byzas founded a city on the promontory and named it Byzantium after himself. The location of Byzantium attracted Roman Emperor Constantine I who, in AD 330, moved the capital of the Roman Empire there and renamed the city the  Nova Roma. After his death the city was called Constantinople, the capital of the Eastern Roman Empire, also called the Byzantine Empire.

After the fall of the Western Roman Empire in 476, the Byzantium carried on the legacy of the Roman Empire for another millenium. In 1453, the city was conquered by armies of the Ottoman Empire and, renamed Istanbul, became its capital.