Conversation so far:
What was Eleanor of Aquitaine's inheritance?
Eleanor of Aquitaine's inheritance were the lands held by her father, the Duke of Aquitaine.
What else can you tell me about Eleanor of Aquitaine's inheritance besides inheriting the lands held by her father?
As these were the days when kidnapping an heiress was seen as a viable option for obtaining a title, William X dictated a will on the very day he died
So there was a fear Eleanor of Aquitaine would be kidnapped?
William of Aquitaine dictated a will on the very day he died that bequeathed his domains to Eleanor and appointed King Louis VI of France as her guardian.

Question: Why is that?
Self-contained rewrite: Why is it that William of Aquitaine appointed King Louis VI of France as the guardian of his daughter, Eleanor of Aquitaine?