- The name of the département (department) within which Brussels constituted the chief town (préfecture) during the French regime, it derives from the Dyle (Dijle) River that flows through Brabant. As of 31 August 1795 the provinces of Belgium were abolished and nine départements were created, each headed by a prefect ( préfet), following the political divisions established in France under the French republic (1790). The département of the Dyle consisted of three arrondissements (districts)—Brussels, Leuven, and Nivelles. Each arrondissement was in turn subdivided into cantons and the cantons into municipalities.
Historical Dictionary of Brussels. Paul F. State.