Wallingford Castle, like Windsor closer to London, straddles the Thames in Berkshire not far from Oxford, and has been an important and strategic fortress since the days of the Anarchy, during which time it escheated to royal control. John used it in his rebellion against his brother King Richard and later as King John used it in the baronial revolts. It has since been lavishly spent on and expanded. Edward of Caernarfon had given it to Piers Gaveston as part of the latter's Earldom of Cornwall, but it has since escheated back to the crown upon Gaveston's death. It is now in the possession of Queen Isabella as part of her dower.