Well, the main focus for combat and politics will be Italia and Greece. While that may be the case, the entire known world(to the romans) can be gone to and interacted with at will. Doing so may be necessary to raise legions, repulse barbarians, or lobby for allies. I would say the main focus would be on the Romans(And by extension, Egyptians), but I'm also allowing Parthians and Barbarians(Who can work as mercenaries).