It looked like Europe now. But It was calmer back then before WW1
The answer to this is Congress
The answer is - between Europe, Africa and Asia.
The Byzantine Empire had a territory that was spreading on parts of this three continents, more specifically, it had parts of the edges of this three continents which were trading roots both on land and on sea for centuries before. So the Byzantine Empire took advantage of it and grew enormously in power and wealth because it had control over these trading roots.
