Hildegarde of Burgundy
Hildegarde of Burgundy (c. 1056–1104) was a French noblewoman. She was the only daughter of Robert I, Duke of Burgundy with his second wife, Ermengarde of Anjou. She was, and by marriage, Duchess of Gascony and Aquitaine.
William’s birth was a cause of great celebration at the Aquitanian court, but the Church at first considered him illegitimate because of his parents’ consanguinity. This obliged his father to make a pilgrimage to Rome soon after his birth to seek papal approval of his marriage to Hildegarde.