The city of Constantinople is an ancient city in modern-day Turkey that’s now known as Istanbul. First settled in the seventh century B.C., Constantinople developed into a thriving port thanks to its prime geographic location between Europe and Asia and its natural harbor. In 330 A.D., it became the site of Roman Emperor Constantine’s “New Rome,” a Christian city of immense wealth and magnificent architecture. Constantinople stood as the seat of the Byzantine Empire for the next 1,100 years, enduring periods of great fortune and horrific sieges, until being overrun by Mehmed II of the Ottoman Empire in 1453.

Early in the following century, the Balkan Wars, World War I and the Greco-Turkish War wiped out the remains of the Ottoman Empire.

The 1923 Treaty of Lausanne formally established the Republic of Turkey, which moved its capital to Ankara. Old Constantinople, long known informally as Istanbul, officially adopted the name in 1930.

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