Constantinopole was located in a geographic crossroad , its position was strategic and it´s still so for Turkey under its current name, Istambul.
Because of this location , the capital of the Byzantine Empire was able to receive cultural influences from Europe and Asia, from many countries. Though it was a major theological center of Christianity and a heir to Grecorroman culture, its location got it exposed to Islamic, Turkic, Persian, Caucasian, European and Jewish influences. Because it was the last point of the trade routes with Asia and one of the ending posts of the Silk Road, Constantinopole was a cosmopolitan metropolis for a good part of its history.
"<span>They found the soil unusable, and they had to rely on fishing and hunting for food" is generally true, although some people were able to soil rich enough for farming. </span>
The main way in which domesticating livestock allowed civilizations to spread is that people were freed up to do other things like woodworking and opening shops, since they no longer needed to hunt and gather their food and resources.