What time period we talking about? Constantinople has been through time for more then 2,000 years, Byzantium, Constantinople, Istanbul.
Throughout the roman era it was the biggest trade hub of the east, and was hence forth the capital of the Eastern Roman empire. Which survived for 1,000 years, when Byzantium fell in the 1400's to the ottomans, the ottomans declared Constantinople their capital, and renamed it Istanbul.
B) Survival of the fittest, The fittest to live in that environment
The Empire changed the city's name to Istanbul, made it the capital, and turned the important church into a mosque.
When Constantinople was conquered by the Ottoman Turks, they turned the Hagia Sophia into an Imperial Mosque and renamed the city Istanbul.
Explanation:
One side supported slavery, one side didnt. this resulted in a dispute, which led to war
One way is that nations are getting more advanced weapons. Another way is that it allows more and better factories, and more advanced agriculturaly.