Which city was the capital of the Eastern Roman (Byzantine) Empire?

Constantinople was the capital of the Eastern Roman, or Byzantine, Empire.

Emperor Constantine the Great refounded the ancient Greek city of Byzantium as Constantinople, dedicating it as a new imperial capital in 330. Its position beside the Bosporus gave it control over a major route between the Black Sea and the Mediterranean and between Europe and Asia. Strong walls, a protected harbor, and access to important trade routes helped make it one of the medieval world’s great cities.

After the Roman Empire was permanently divided in 395, Constantinople became the political and religious center of the eastern half. The city was also called New Rome, and its inhabitants considered themselves Romans, although Greek became increasingly dominant in administration and culture.

The Fourth Crusade captured Constantinople in 1204, but the Byzantine government recovered the city in 1261. Ottoman forces conquered it in 1453. It later became widely known as Istanbul; Ankara became the capital of the Republic of Turkey in 1923, while Istanbul remains the country’s largest city.