Medieval cities

THE Roman Empire, at the end of the third century, had one outstanding general characteristic: it was an essentially Mediterranean commonwealth. Virtually all of its territory lay within the watershed of that great land-locked sea; the distant frontiers of the Rhine, the Danube, the Euphrates and the Sahara, may be regarded merely as an advanced circle of outer defences protecting the approaches.The Mediterranean was, without question, the bulwark of both its political and economic unity. Its very existence depended on sea mastery. Without that great trade route, neither the government, nor the defence, nor the administration of the orbis romanus would have been possible.As the Empire grew old this fundamentally maritime character was, interestingly enough, not only preserved but was still more sharply defined. When the former inland capital, Rome, was abandoned, its place was taken by a city which not only served as a capital but which was at the same time an admirable port—Constantinople.