Restormal Castle occupies a knoll above the River Fowey, a mile north of Lostwithiel. Its plan is quite a curiosity. A perfectly circular bailey with a set of internal buildings arranged concentrically against the curtain. The domestic buildings are all ruined but the curtain is virtually intact. The sense of compactness is heightened by the absence of an outer bailey, because although one existed every trace has disappeared.
There is no historical reference to the castle until 1264, when Simon de Montfort seized it, but Restormel is clearly older than that. From outside the embattled curtain appears to crown a motte, and the structure is often described as a large shell keep, but the “motte” is really a ringwork. Furthermore the inner bank was removed when the curtain was built, so the rampart now looks as if it has been heaped against the outside.
In 1270 the castle passed to the earls of Cornwall and enjoyed a brief ascendancy. Earl Edmund chose Lostwithiel as his administrative center and Restormel became his residence. It is to this era that we owe the interesting apartments which back onto the curtain, resulting in a bewildering group of curved chambers. An inventory of 1337 identifys these apartments as the kitchen, hall, solar, ante-chapel and two large guest chambers. Apart from the kitchen, the main apartments all stood at first-floor level over cellars.
The chapel, reached from the ante-chapel, occupied a contemporary square tower which projects boldly from the line of the curtain. A square mural tower in the Edwardian age is typical of Cornish conservation. At the death of Edmund in 1299 the earldom reverted to the Crownm and with the creation of the duchy the castle was seldom visited. The only military episode was a siege in 1644, when it fell briefly into Royalist hands.