Constantinople has colonized a lot of worlds.  Of course it’s Constantinople, capital of empires, center of trade for millennia, ancient and powerful and all that jazz.  Sure she was getting a bit long in the tooth by the time we started our space race, and I’m betting she was working more on reputation than actual capability by then.  But reputation can count for a lot.  And when Constantinople shrugged the Jihad off her walls, she had a lot of reputation to spend.