In 1285, while Charles II of Naples, nominal prince of Achaea, was imprisoned, Robert of Artois, regent of the kingdom, named William bailiff and vicar-general of Achaea.
In 1285, when Charles II of Naples, who served as a nominal prince in Achaea, was imprisoned, Robert of Artois, acting as the kingdom's regent, appointed William to be bailiff and vicar-general of Achaea.