: Roman Emperor Constantine the Great recognized its value and made it the new capital of the Roman Empire. For over a millennium, it was the wealthiest and most powerful city in the Christian world.

The story of Istanbul is a grand epic spanning over 2,500 years, characterized by its unique position as the only city in the world straddling two continents—Europe and Asia. Its narrative is one of transformation, evolving from a Greek colony to the majestic capital of two of history's greatest empires before becoming the vibrant cultural heart of modern Turkey.

: After the Ottoman conquest by Mehmed II in 1453, the city became the seat of the Ottoman Empire for nearly 500 years. It was officially renamed Istanbul in 1930. Architectural Landmarks and Layers

Istanbul's history is often told through its three distinct eras and names:

: Founded by Greek settlers from Megara, the city began as a strategic trading post on the Bosphorus.