Answer:
Byzantium, later known as Constantinople, has been, throughout history, an important place for trade, thanks to its priviliged geographical location, between Europe and the Middle East, and between the Aegean Sea, and the Black Sea, connected by the Strait of Bosphorus.
The effect so much trade in Byzantium was that the city became 1) wealthier, because of the amount of goods and services that reached the city, and 2) more politically powerful, because of the importance of the trade relations centered in and around Byzantium, not only for Byzantium itself, but also for other nations.
