[3] Sir John des Roches ordered the castle built around 1330, about the time of the start of the Hundred Years' War.

The castle's position on a clifftop 200 ft (~ 60 m) above the sea means that the natural features of the site protect it on three sides.

Governor Harliston approved the dismantling of the ″fort of refuge″ at Grosnez so that the already-worked stone could be re-used in fortifying St. Ouen's Manor.

When Matthew Baker was sent to take Harliston's place in 1486, the Seigneur had not paid his taxes to the Exchequer for three years - since the death of Edward IV.

When King Henry VII ordered a general examination of outstanding accounts by the Exchequer clerks, it was inevitable that De Carteret would be required to pay the back taxes he owed the Crown.