The Estates (États, Staten) comprised the governing institution of Brabant under the ancien régime. It consisted of three bodies: the First Estate, the high clergy; the Second Estate, the nobility; and the Third Estate, the urban magistrates and guild leaders of Brussels and other provincial cities and towns. They met in the Assembly Hall of the Hôtel de Ville, in which the first two estates occupied chairs in the center of the hall and the members of the Third were seated on benches under the windows. The sovereign, in the person of the governor-general, convened the Estates twice a year (March and October), whose approval was needed, most especially, for tax levies. The institution was abolished during the French regime.
Historical Dictionary of Brussels. Paul F. State.