In any given geography, the central territory will always be the place of greater volume of population, more business opportunities, market opportunities, information dispersion through media and technology. It will always be the major target. So, if colonizers would like to conquer slowly, they have to start in provincial areas. There will be less hurdles to breach through because circumstances are less advanced. It will be easier to control. This will buy them more time and preparation to eventually conquer the capital.