Answer:
Constantinople is Formerly known as Byzantium.
Explanation:
Byzantium is of Thraco-IIIyrian origin, there is a myth that this place was formerly settled by a Megarian colonist, Byzas. Constantinople was the first Roman emperor who laid stones for this city so in remembrance of him, the city is known as Constantinople.
The city of Constantinople is the richest in Europe during its time and it is the gateway between Asia and Europe, this city is almost impenetrable with two walls on one side and the sea on the other side. In present days, this city is called as "Istanbul".