The institutional reform of the Belgian state seems to run parallel with a redefinition of the whole of Belgian society. 'Subnationalism' has overtaken the traditional ethno-linguistic definitions which used to provide a basis for political identification and mobilisation. The territorial demarcation of the regions and the politicisation of cultural life on both sides of the linguistic border constitute basic ingredientsfor 'nationbuilding'projects in Flanders and Wallonia. A number of elements are distinguished to explain why the 'nationalism' of the regions will have repercussions on the political developments in the capital area. Language and territoriality have always played a special role in Brussels. Changes in connection with definitions of territoriality and identity now seem to create opportunities to redefine the relationship between the communities in Brussels. It is not inconceivable that, in the long run, the linguistic divide wilt fade out and wilt be replaced by an identification on the basis of a territorial criterion shared by all the Brussels' inhabitants.