The 10 strongest castles in France

Built by Richard the Lionheart in barely two years (1196-1198), Gaillard was the most advanced castle of its age: three baileys stepped along a limestone promontory 90m above the Seine and split by rock-cut ditches, an inner curtain of scalloped spur-shaped bastions that shrugged off missiles and gave archers overlapping fire, and among the earliest machicolations in the West.

It fell only once, and it took the King of France to do it. Philip II besieged it from 1203; over roughly six months his men filled the outer ditch and undermined a tower to take the outer bailey, then slipped into the middle ward by climbing a latrine chute into the chapel and forced the inner gate. The garrison surrendered on 6 March 1204 and Normandy fell with it. It changed hands repeatedly in the Hundred Years War before France held it for good from 1449.

Coucy carried the largest keep ever raised in medieval Europe: a cylindrical donjon about 35m across and 55m tall, ringed by four corner towers some 20m in diameter, each as large as the royal keeps the French crown was building elsewhere. The whole enceinte stood on the tip of a bluff above the town, a defence built on sheer mass rather than trickery.

Its reputation rests on scale, not on a great siege withstood: no army ever stormed it. Cardinal Mazarin had the fortress partly slighted in 1652 after the Fronde, and the colossal keep still dominated the ridge until March 1917, when the retreating German army packed it with explosives and blew it apart, an act condemned across Europe as vandalism rather than military necessity.

One of the largest fortresses in Europe by ground area, Fougeres sprawls across a rock in a marsh, wrapped by a loop of the Nancon that fed a water-filled moat, so an attacker could neither mine the walls nor drag engines across the swamp. Thirteen towers guard three successive enclosures, the innermost shielding the keep.

The stone castle grew after Henry II of England burned its timber predecessor in 1166. It was never broken by battery but was lost by surprise: in 1449 the mercenary Francois de Surienne, in English pay, seized it in a raid, and the outrage helped trigger the French reconquest of Normandy. A French army retook it after a siege in 1488, which ended its fighting life.

Bonaguil is the last great castle of the French Middle Ages, rebuilt around 1480-1520 by Berenger de Roquefeuil as a fortress designed from the ground up for gunpowder: a 350m outer wall backed by an earth mass to soak up cannon shot, roughly a hundred gun-loops and casemates, caponiers to sweep the rock-cut ditches with crossfire, a barbican and drawbridges, all on a narrow rocky spur. Its 'never taken' record is literal but hollow, because no army ever attacked it. Militarily obsolete almost as soon as it was finished, it was merely seized amid the civil disorder of the Wars of Religion in 1563, never tested by a formal siege.

The largest of the Cathar 'citadels of the sky', Peyrepertuse runs the whole crest of a limestone ridge at about 800m, its walls rising straight off cliffs of 30 to 40m, as vast as the walled city of Carcassonne and reachable only by a single exposed approach. Terrain, more than masonry, made it near-impregnable. It was never stormed: after the crusaders crushed the Trencavel revolt at Carcassonne, its lord submitted in 1240 and handed it over. Louis IX then added the higher Sant Jordi keep in 1250-51, tightening a position no medieval army seriously tried to assault.

Fort la Latte guards a Breton headland all but surrounded by sea, cut off from the mainland by two deep clefts crossed only on drawbridges, with a barbican and a compact 14th-century keep behind them; later engineers added bastioned gun-works and a furnace for heating shot to fire at wooden ships. It held firm when an English force besieged it fruitlessly in 1490. Its walls did fall once, though: in 1597, during the Wars of Religion, Catholic League troops took and burned it because its Matignon lord backed Henri IV, and only the granite keep came through the sack intact.

Vincennes is built around the tallest medieval keep in Europe, a 52m donjon of nine storeys inside its own walled and moated compound, set within a rectangular curtain over a kilometre round, studded with towers and ringed by a deep stone-lined ditch. The scale of the defences is exceptional; the war record is not. Standing on flat ground east of Paris with no natural strength, it was never subjected to a serious storming. Henry V of England held it from 1420 and died there in 1422, and in 1814 its governor Daumesnil famously refused to surrender to the Allies. It is a colossal fortress that was rarely, if ever, truly put to the test.

Haut-Koenigsbourg sits on a Vosges spur at about 755m, a mountain fortress reworked with artillery bastions and a great gun-bastion in the 15th and 16th centuries. But its record is one of defeat, not endurance: in 1633, during the Thirty Years War, Swedish troops besieged it for 52 days, then burned and looted it, and it lay a ruin for nearly three centuries. Crucially, the building visitors see today is not a medieval survivor but a 1900-1908 reconstruction by Bodo Ebhardt for Kaiser Wilhelm II, an interpretation of the pre-1633 castle (the rebuilt keep is admittedly some 14m too tall). No standing wall here ever withstood a medieval siege.

Loches is one of the earliest and mightiest stone keeps in Europe, an 11th-century rectangular donjon raised by Fulk Nerra of Anjou, about 37m high with walls near 3m thick, on a spur above the town. As a single great tower it was formidable, but as a keep-and-enceinte it lacked the layered rings of later fortresses. It was taken more than once: Richard the Lionheart stormed it on 13 June 1194 to wrest it back from the French, and Philip II of France, after earlier failing against it, finally besieged and captured it in 1204 as Angevin power in the region collapsed.

Queribus perches on the highest crag for miles at about 728m, a knot of walls and a polygonal keep clinging to bare rock, one of the 'five sons of Carcassonne' and the last Cathar refuge to hold out. Its strength is almost entirely the cliff; the garrison was small and the built works modest. When a royal force under Olivier de Termes arrived in 1255 there was no real fight: the commander Chabert de Barbaira surrendered in murky circumstances, deceived or bought by his old friend Olivier, and the defenders appear to have slipped away rather than be stormed out. Its fall was capitulation, not conquest.