The Dukes of Navarre were the rulers of the historical region of Navarre, located in present-day northern Spain and southwestern France. The title emerged in the late Middle Ages, with the dukes often playing significant roles in the political and military affairs of the region. The most notable duke was Henry IV of France, who was originally Henry III of Navarre before ascending to the French throne. The Dukes of Navarre were part of a complex feudal system and often engaged in conflicts with neighboring territories. Their lineage is tied to the House of Bourbon, which later became prominent in French history. The title of duke was eventually absorbed into the French crown, diminishing the political power of Navarre.