The 1648 Peace of Westphalia ceded present-day North Brabant (Dutch: Noord-Brabant) to the Generality Lands of the Dutch Republic, while the reduced duchy remained part of the Habsburg Netherlands until French Revolutionary forces conquered it in 1794 — a change recognized by the Treaty of Campo Formio in 1797.

Today all the duchy's former territories, apart from exclaves, are in Belgium except for the Dutch province of North Brabant.

In 959 the East Frankish king Otto I of Germany elevated Count Godfrey of Jülich to the rank of duke of Lower Lorraine.

In 962 the duchy became an integral part of the Holy Roman Empire, where Godfrey's successors of the ducal Ardennes-Verdun dynasty also ruled over the Gau of Brabant.

After the Battle of Worringen in 1288, the dukes of Brabant also acquired the Duchy of Limburg and the Lands of Overmaas (trans-Meuse).

In 1430 the Duchies of Lower Lotharingia, Brabant and Limburg were inherited by Philip the Good of Burgundy and became part of the Burgundian Netherlands.

At that time the Duchy extended from Luttre, south of Nivelles to 's Hertogenbosch, with Leuven as the capital city.

Brabant was included in the unrecognised United States of Belgium, which existed from January to December 1790 during short-lived revolt against Emperor Joseph II, until imperial troops regained the Austrian Netherlands for Leopold II who had succeeded his brother.

Trade was allowed in the walled areas and usually this right resulted in a larger population and the development of major villages and later cities.

Note: the city of Mechelen formed an independent state along with the Land of Heist-op-den-Berg and Gestel.