The Duke of Aquitaine was a title in the medieval French nobility, associated with the region of Aquitaine in southwestern France. This title was significant during the Middle Ages, especially when the duchy was one of the largest and most prosperous territories in France. The dukes played a crucial role in the political landscape, often influencing the relationship between the French crown and the English monarchy. One of the most famous holders of the title was Eleanor of Aquitaine, who became queen consort of both France and England. Her marriages and political alliances helped shape the history of both nations. The duchy itself was eventually absorbed into the French crown, but its legacy remains an important part of European history.