Philip married Isabella of Villehardouin , Princess of Achaea and co-reigned with her from 1301 to 1307 .
Their claim to the throne of Achaea came from her great - grandfather Philip of Savoy , eldest son of Thomas III of Piedmont and Guia of Burgundy .
son married Isabella of Villehardouin , Princess of Achaea and co-reigned with her from 1301 to 1307 .
Their claim to the throne of Achaea came from her great - grandfather Philip of Savoy , eldest son of Thomas III of Piedmont and Guia of Burgundy .