The title "Duke of Brabant" refers to a historical noble title in the region of Brabant, which is now part of modern-day Belgium and Netherlands. The title was established in the 12th century and was held by various rulers, including members of the House of Reginar and later the House of Habsburg. The dukes played a significant role in the political and economic development of the region. Brabant was an important center during the Middle Ages, known for its prosperous cities and trade. The title of Duke of Brabant eventually became part of the larger title of the Duke of Brabant and Limburg and was absorbed into the Burgundian Netherlands in the 15th century, influencing the region's history significantly.