The Landgraviat of Brabant must be distinguished from the Duchy of Brabant. The Duchy of Brabant was initially a feudal elevation of the landgraviat, but its name was applied to the entire country under the control of the Dukes of Brabant, from the 13th century on.
This imperial fief was assigned to Henry III, Count of Leuven about 1085/1086, more exactly after the death of the preceding Count of Brabant, Count Palatine Herman II of Lotharingia (d. September 20, 1085).
The county was quite small: it was limited to the territory between the rivers Dender and Zenne, situated to the west of Brussels.