The 12C fortress, once the pivot of the duchy of Valois' defences, was first remodelled under Louis of Orléans by the architect Jean le Noir. The castle was, however, dismantled in the 17C. In 1813, Napoleon I bought the ruins for less than 3 000 gold francs. His nephew, Napoleon III, entrusted the restoration to Viollet-le-Duc in 1857. Initially the brief involved restoring parts of the castle to an inhabitable condition, but by 1861 it was decided to turn Pierrefonds into an Imperial residence. Fascinated by medieval life and Gothic architecture in particular, the architect set about rebuilding the castle completely, and the work lasted until 1884. At present, each of the eight defensive towers bears a statue of a military hero (preux): Arthus, Alexander, Godefroy, Joshua, Hector, Judas Maccabaeus, Charlemagne and Caesar. The main front of the inner courtyard appears with its basket-handled arcading forming a covered shelter surmounted by a gallery (a detail invented by Viollet-le-Duc). The first floor of the keep became the Imperial couple's rooms, also designed by the same architect. The timber-ceilinged hall (52m x 9m) of the "Salle des Preuses" is shaped like an upturned ship. The mantelpiece is decorated with statues of nine heroines from tales of chivalry (hence the room's name). Finally the northern sentry walk features all the finer architectural points of medieval defensive systems (level walkways without steps and no narrow doors, to avoid blundering into obstacles).