William X of Aquitaine was a prominent nobleman in the 11th century, known for his role as the Duke of Aquitaine from 1126 until his death in 1137. He was a member of the House of Poitiers and played a significant part in the political landscape of medieval France. His reign was marked by efforts to strengthen the duchy and maintain its independence from the French crown. William X was also the father of Eleanor of Aquitaine, who would become one of the most influential women in medieval Europe. His marriage to Aenor de Châtellerault solidified alliances and helped to enhance the power of Aquitaine during his rule.