Constantinople is the last great non-aligned power.  The City stretches from the Mediterranean to the Black Seas, and has been a major center of trade for thousands of years.  When humanity went to the stars, The City sent scouts to find stars they judged to be in good locations for future trade.  They colonized very few, but those few are the richest trading centers in all of Terran space.  Any trader that ever lived has been to at least one of those worlds.