Newbury Castle is the name of an English adulterine castle built by John Marshal during The Anarchy. It is located west of the town of Newbury in the English county of Berkshire. The Castle is mentioned in the "L'Histoire de Guillaume le Marechal" (History of William the Marshall) wherein it describes King Stephen as besieging the castle in 1152 and holding Marshal's son, William Marshal, as a hostage against Newbury's surrender. When the elder Marshal refused to comply, Stephen threatened to have the young boy catapulted over the walls. John, ("that child of hell and root of all evil" according to Henry of Huntingdon) responded defiantly, "I have the anvils and the hammer to forge still better sons." King Stephen wasn't so heartless though—he relented and the boy survived.