Er war Patenkind seines Onkels Theodoricus III., Graf von Autun, der das Kind vor seinem Tode um 827 der Obhut von Kaiser Ludwig dem Frommen anvertraute. ###>William was initially sent to the court of his uncle, Theodoric of Autun, who died around 830, and left the child in the charge of Louis the Pious, then reigning Emperor.