feudal duchy that emerged after the decline and collapse of the Frankish Carolingian empire in the mid-9th century. Centred in Louvain (now Leuven) and Brussels, it was a division of the former duchy of Lower Lorraine, which was split up into Brabant, Luxembourg, Hainaut, Namur, and other small feudal states in the 11th century.

The remnant of the duchy of Lower Lorraine was held by Henry I the Warrior of the House of Louvain, who in 1190 assumed the title of duke of Brabant. Three generations of his heirs ruled relatively peacefully. In 1283 John I of Brabant bought the duchy of Limburg from Adolph V of Berg and secured this acquisition by defeating and slaying his competitor, Henry of Luxembourg, at the Battle of Woeringen (June 5, 1288).

In exchange for the financing of their military and court expenditures, the dukes of Brabant had to guarantee the rights and privileges of various local lords and burghers. By the charter of Cortenberg (Sept. 27, 1312), for example, Duke John II entrusted the imposition of taxes to a council of burghers and nobles who would oversee the maintenance of justice and the equal application of the laws. The next duke, John III, proved a shrewd diplomat who strengthened the duchy by advantageous marital alliances with neighbouring principalities. When Johanna, the daughter of John III, and her husband, Duke Wenceslas of Luxembourg, acceded to the duchy of Brabant, they granted the charter of rights known as the Joyeuse Entrée (q.v.; Jan. 3, 1356). This great constitutional charter gave Brabant an exceptional position among the feudal states of the Low Countries and allowed it to play an eminent role in later centuries in the resistance against absolutist rulers.

When Johanna succeeded to the title of Brabant, however, she was challenged by her sister's husband, Louis II, count of Flanders. During the ensuing strife, Johanna continued to rule Brabant and, after Wenceslas' death, Luxembourg, but she had to rely for aid on the house of Burgundy. In 1390 she ceded her rights to her niece Margaret of Flanders, who was married to Philip II the Bold of Burgundy. When the family line died out in 1430, inheritance passed to Philip III the Good of Burgundy, an event that marked the end of the independent existence of the duchy of Brabant. The duchy passed to the house of Habsburg (Habsburg, House of) in 1477 upon the marriage of Philip's granddaughter, Mary, to the archduke Maximilian. Control of the duchy passed to the Spanish Habsburg king Philip II in 1556.

Under Philip's rule there began the Eighty Years' War (1568–1648), in which the Dutch achieved their independence from Spain. In the course of that prolonged struggle, Brabant was divided into northern and southern portions. The south remained under Spanish rule, and the north went to the Dutch. With a few additional tracts, the northern portion now forms the Dutch province of Noord-Brabant (q.v.; North Brabant).

The southern portion remained a Spanish possession until it was ceded by the Treaties of Utrecht (1713) to the Austrian Habsburgs. In the Brabant Revolution of 1789–90, the province mounted an unsuccessful armed resistance to the Austrian emperor Joseph II's abrogation of the Joyeuse Entrée. Southern Brabant eventually became part of Belgium and is currently divided into the provinces of Flemish Brabant and Walloon Brabant.

The influence of Brabant's democratic and constitutionalist traditions on the modern Belgian state is attested to by the flag of Belgium, which uses the Brabançon colours—red, yellow, and black. The title of duke of Brabant has been revived as the style of the eldest son of the king of Belgium.