The Duchy of Brabant was formally erected in 1183/1184. The title "Duke of Brabant" was created by the German Emperor Frederick Barbarossa in favor of Henry I, son of Godfrey III of Leuven (who was Duke of Lower Lotharingia at that time). The Duchy of Brabant was a feudal elevation of the since 1085/1086 existing title of Landgrave of Brabant. This was an Imperial fief which was assigned to Count Henry III of Leuven shortly after the death of the preceding Count of Brabant, Count Palatine Herman II of Lotharingia († September 20, 1085). Although the corresponding county was quite small (limited to the territory between the rivers Senne and Dender) its name was applied to the entire country under control of the Dukes from the 13th century on. In 1190, after the death of Godfrey III, Henry I also became Duke of Lotharingia. Formerly Lower Lotharingia, this title was now practically without territorial authority, but was borne by the later Dukes of Brabant as an honorific title.
In 1288, the Dukes of Brabant became also Duke of Limburg. The title fell to the Dukes of Burgundy in 1430. Later on, it followed with the Burgundian inheritance until the French Revolution, although the northern part of the territory of Brabant was actually governed by the United Provinces during the 17th and 18th century (see Generality Lands).
In the modern Kingdom of Belgium, the title of "Duke of Brabant" revived as honorific title and is traditionally assigned to the Crown Prince (even though the province of Noord-Brabant, part of the historical duchy, is now part of the Netherlands).
It is unknown whether the presumed Crown Princess, Elisabeth, will be styled Duchess of Brabant or not.
The title Duke of Brabant is one of the titles of the Spanish Crown.