The Duke of Aquitaine was a title held by the rulers of the historical region of Aquitaine in southwestern France. This title became prominent in the medieval period, particularly during the 10th to 15th centuries. The dukes played a significant role in the political landscape of France and were often involved in conflicts with the French crown. One of the most notable figures to hold this title was Eleanor of Aquitaine, who was married to both Louis VII of France and Henry II of England. Her marriages significantly influenced the power dynamics between France and England, as Aquitaine was a valuable territory that contributed to the wealth and influence of its rulers.