What was the ancient name of Istanbul?

The ancient name of Istanbul was Byzantium. Founded by Greek colonists from Megara around 657 BC, Byzantium became a significant trade hub and strategic city due to its location connecting Europe and Asia. It maintained this name for many centuries until it was renamed Constantinople in AD 330, when Emperor Constantine the Great expanded and reestablished the city as the new capital of the Roman Empire. This transformation marked a new era in the city's history. Istanbul is the modern name of the city, having evolved over time through various cultural influences, but its roots trace back to the original name, Byzantium. This historical context makes Byzantium a critical part of understanding the city's legacy.