Re–founding of Constantinople on the site of an already existing city, Byzantium, settled in the early days of the Greek colonial expansion around 671–662 BCE. The new walled capital of the Roman Empire is built–up by Constantine I and named after him.
Constantinople is astride the Bosporus and the Marmara Sea. The western side of Constantinople (the walled part) on the Bosporus is Europe, and the eastern side, Asia. The city is astride the route from the Black Sea to the Mediterranean. The sequential sea route north to south is: Black Sea > Bosporus Strait > Sea of Marmara > Dardanelles Strait > Aegean Sea in the Mediterranean.
Constantinople was renamed “Istanbul” in 1930 by Ataturk.