Three historical phases can be identified in the Belgian territorial organisation. During the « Ancien régime », Belgium doesn’t exist as such. Even if the principalities which will constitute present Belgium are ruled by the same Sovereign,except for the episcopal principality of Liège, he will not be able to impose a strong centralised administration against the resistances of the traditional counter-powers and another territorial pattern than the complex one inherited from the feudal situation. The incorporation of the present Belgian territory to the French Republic and Empire will impose the rational division in “départements” and municipalities, well adapted to a yet mainly rural economy. The United Kingdom of the Netherlands (1814-1830), followed by the independent unitary Belgium keep this territorial pattern, replacing only the names of the former “départements” by more legitimate historical references. The evolution towards a federal structure during the last half-century prescribes re-drawings following politico-linguistic rationales, but these ones are not taking into account Brussels metropolitan and cosmopolitan developments, even if they are at the core of the Belgian economic prosperity