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Vauban, France’s master engineer of the 17th Century, designed nearly 100 fortress for Louis XIV—and defined the form for the ages.

Sébastien Le Prestre, who would earn renown as seigneur de Vauban and a marshal of France, was born in 1633 in a small village in Burgundy. Vauban (as he is generally known) was of minor provincial nobility with few influential family connections. He spent his early military career in the service of Louis de Bourbon, prince of Condé, during the civil war known as the Second Fronde (1650–53), as a rebel fighting against young King Louis XIV. Though royalists captured Vauban early on, the reputation the young soldier had already established stood him in good stead, for rather than being hanged as a rebel, he was interviewed by Cardinal Jules Mazarin, the king’s Italian-born adviser. Mazarin was sufficiently impressed to offer Vauban a place in Louis’ army, and the young man prudently changed sides.

Gifted with an inquiring and open mind, prodigious energy and a capacity for long hours and hard work, Vauban soon established a reputation as a gifted military engineer. He was a student of such eminent predecessors as Blaise-François, comte de Pagan (1604– 65), and blessed with a good measure of practical common sense, he developed a particular interest in both the design and construction of fortresses to modern pattern, and in the most effective ways to capture those same places at the least cost.

By the late 17th century, fortress design was based on the simple plan of the trace italienne, or star fort. The high stone walls of medieval castles had given way to low, sharply sloped, artillery-resistant embankments. This system employed geometric patterns superimposed one on another, enabling fortresses largely to withstand the devastating effects of modern gunpowder artillery and mining. The design also met the timeless demands of effective defense—establishing clear lines of fire and ensuring concealment, depth and protection. Of course, topographical variations and complexities in any location meant that a successful fortress designer had to bring his ingenuity and imagination to the basic plan, and in that regard Vauban proved a master of his craft. Any force seeking to capture one of his fortresses would pay a significant price in time, effort and blood. With his complementary keen interest in the best way to seize fortresses, Vauban also drew up a model timetable for a besieging commander, setting out in detail how his force might employ the suggested 48 days to good effect.

With the civil wars settled, Louis XIV embarked on a series of aggressive campaigns against his neighbors. In May 1667 French armies under the command of such remarkable soldiers as Marshals Henri de la Tour d’Auvergne, vicomte de Turenne, and François-Henri de Montmorency, duc de Luxembourg, marched into the Spanish Netherlands (present-day Belgium and Luxembourg) and soon placed large parts of Artois, Picardy and Flanders under French control. Having pushed his northern border outward, Louis XIV naturally wanted to strengthen the existing obsolete defenses there. His chief engineer, Louis Nicolas de Clerville, was unwell, so the king gave young Vauban the task of redesigning and strength ening the defenses of Lille, an undoubted honor for a man still junior in rank.

The remodeling and rebuilding of Lille was an enormous undertaking, the massive new citadel alone requiring some 60 million bricks. Laborers completed the work in 1674, and this set the pattern for future years, as Vauban continually hurried across France on instructions from Louis XIV and his minister for war, François-Michel le Tellier, marquis de Louvois, to survey existing defenses, devise and recommend improvements, and oversee the construction of strong new fortifications. The king could for the time being foot the vast expense, and between 1668 and 1698 Vauban designed a strong double belt of modern fortresses to shield France’s northern border, where no really strong natural obstacles existed. This system of defense was known as the pré carré (“square field”), or Fence of Iron. Among its key attributes was mutual support; Vauban’s declared intention was that no French fortress on the northern border should be out of hearing of cannon-shot from another fortress.

Renewed war, whether in search of glory or as a defensive measure against encroaching neighbors, was a regular theme of Louis XIV’s reign. The Netherlands, Spain, Austria, England (Great Britain from 1707 onward) and the German princely states all felt the power of French armies between 1672, when Louis and allies attacked the Dutch Republic, and the close of the Nine Years’ War (War of the League of Augsburg) in 1697. Armies had maneuvered, fought battles, and besieged, bombarded and stormed fortresses, but none of the warring parties had achieved anything of real value, other than Louis’ success at securing territorial gains, while firmly establishing the suspicions and enmity of his neighbors.

With the nations of Western Europe exhausted by war, fresh conflict was unwelcome. But when childless King Charles II died in Madrid in November 1700, he left the throne of Spain to Philip, duc d’Anjou, the youngest grandson of Louis XIV. If refused, the throne would immediately be offered to Archduke Charles, the second son of Holy Roman Emperor Leopold I of Austria—thus setting the stage for the War of the Spanish Succession.

Accordingly, Louis XIV allowed his grandson to accept the Spanish throne. Diplomacy failed, conflict could not be avoided, and in the spring of 1702 a Grand Alliance of Austria, England and the Dutch Republic declared war on France and Spain. John Churchill, 1st Duke of Marlborough, took field command of the Anglo-Dutch army, and two years later he took his army to Bavaria, where, with Austrian commander Prince Eugene of Savoy, he defeated the French and Bavarian armies at the Battle of Blenheim.

This defeat seriously weakened Louis XIV’s war-making capacity. Just 18 months later, on May 23, 1706, Marlborough’s utter destruction of Marshal François de Neufville de Villeroi’s French army at Ramillies laid bare the whole of the Spanish Netherlands. In the space of few short weeks such important places as Brussels, Leuven, Antwerp, Ostend, Dendermonde and Ath had fallen to Marlborough. The victorious allied army stood at the borders of northern France, and only the Fence of Iron, the fortress belt constructed under Vauban’s direction over the previous 35 years, remained to support the threadbare forces left to defend France from invasion.

At this time of peril 73-year-old Vauban, now a marshal of France and addressed by Louis XIV as mon cousin (“my cousin”), was unwell and in semiretirement. The king nonetheless summoned him to active service and gave him command of the troops that could be spared to defend the English Channel coastline from Gravelines to Dunkirk. This was a sideshow but not unimportant, and Vauban found time to construct a stout fortified camp at Dunkirk that proved so good in its simple layout that French troops put it to use 80 years later during the French Revolution. The Grand Alliance failed to follow up on the victory at Ramillies, and French field commander Louis Joseph, duc de Vendôme, was able to stabilize the situation along the northern border and maneuvered around Vauban’s fortresses to foil Marlborough. This changed in July 1708, when Marlborough forced a sudden battle on Vendôme beside the Scheldt River at Oudenarde and inflicted a severe defeat on the French army.

Vauban knew nothing of it, for he had died at his Paris home in March 1707. The passing of this great man, a giant of his age who would prove the model for all military engineers from then onward, went almost unnoticed, with just a simple family funeral at his home. France was embroiled in a war it could neither afford nor win, so official minds were busily engaged elsewhere. Also, Vauban was in royal disfavor for publishing without authority a treatise on ways to rationalize French taxation. Still, this official neglect was astonishing, for the greatest result of Vauban’s efforts, the construction of a formal defense system for France, was in place, and Louis XIV would find that his deceased engineer now engaged in absentia with France’s opponents in a prolonged passage of arms. French field armies were in tatters, the treasury empty, the wealth of the nation squandered in almost continuous warfare, but if Vauban’s Fence of Iron, his life’s handiwork, held firm, then so too would France.

In the aftermath of the victory at Oudenarde, Marlborough and Prince Eugene laid siege to Lille, the cherished prize of Louis XIV’s early wars. The massive new citadel was a tough obstacle, but the French had to submit in December 1708. Louis XIV regretted the loss of the fortress, but he had gained breathing room, and the prolonged defense had halted the allied campaign. The classic role of the fortress—to tie down an opponent, force him to fight on ground of the defender’s own choosing and eat away at valuable and irreplaceable campaign time—had clearly been realized.

The following September saw Marlborough’s capture of the Vauban-designed fortress of Tournai. Once again the task was formidable, as the citadel was of particularly powerful design and construction. Within a week of that capitulation the allies battled to a Pyrrhic victory in the murderous clash in the woods at Malplaquet, then seized the fortress of Mons. Louis XIV’s commanders would no longer face Marlborough and Eugene in open battle, and campaigning in 1710 saw sieges at Douai, Béthune, Saint-Venant and Aire-surla-Lys, all fortresses that had received Vauban’s attention. Each one fell to Marlborough and his generals, but at a slowly measured pace, the allies’ heavy casualties gradually blunting their effectiveness as a fighting machine.

Meanwhile, Marlborough’s influence in London, established and sustained by success in open battle, was fading. The year 1711 saw the fall of Vauban’s fortress of Bouchain, an achievement calling for great skill and judgment on Marlborough’s part, but it was not enough to save the duke, whom Queen Anne dismissed from service at year’s end. Following renewed French successes in 1712, Louis XIV’s representatives negotiated a generally advantageous peace settlement for their king at the April 1713 Treaty of Utrecht: Philip V remained on the throne in Madrid, but other provisions divided the huge Spanish empire and significantly restricted French power and influence for generations to come.

Between 1708 and 1711, were it not for Vauban’s Fence of Iron, Marlborough and Eugene would have sacked much of France. The War of the Spanish Succession had amply demonstrated the latent power of well-planned fortifications, even when only supported by weakened field armies. But it was not the last time those fortifications would serve France so well.

Maneuver warfare, which frees commanders from the need to shield and protect fixed fortresses, was commonplace in the 18th century. Armies certainly waged desperate battles at such places such as Fontenoy, in 1745, when an allied army challenged the French siege of Tournai, but these tended to be the exception. Still, were it not for the valiant defense of such Vauban fortresses as Tournai, Valenciennes and Cambrai, the French armies of the 1790s and the revolution itself would have failed. Fortress construction proceeded on a lesser scale than before, partly due to the forbidding cost of these structures. But a glance at the defensive plans of such places as Fort Ticonderoga and Fort William Henry in New York, Fort Monroe in Virginia and the citadel of Hue in Vietnam will show that the influence of classic military engineers educated in the Vauban tradition lasted long, and went deep and wide.

Emperor Napoléon I stands as the instantly recognizable military figure of the early 19th century. His campaigns, among the most astonishing in history, demonstrated how little siege warfare had changed, although Arthur Wellesley, 1st Duke of Wellington, certainly put his subordinates to the test in Spain, Portugal and southern France, at such places as Cuidad Rodrigo, Badajoz and Bayonne. Wellington’s impatience to get on with things, and his tendency to incur heavy casualties as a result, would likely not have impressed the rational Vauban, who disdained needless loss of life. Surprisingly, Paris remained unprotected by formal defenses until the work of Baron François-NicolasBenoît Haxo, a devotee of Vauban and his methods, came to fruition in the 1830s. During the 1870–71 Franco–Prussian War ill-prepared French armies gave way to their more dynamic German opponents, and Paris came under bombardment and siege, eventually having to submit. Still, the defenses of the city played their part, as did those of Vauban design in Péronne, Belfort and Verdun, all of which defied German assaults longer than thought likely when facing modern rifled artillery.

In the wake of that sobering defeat the French employed engineer General Raymond Adolphe Séré de Rivierès to establish a new, more formidable and Vauban-inspired fortified line of defenses for northern France. In 1914 fastmoving German armies pushed through neutral Belgium and outflanked the main French fortifications, though the Belgian army’s defense of Liège and Namur impeded the Germans’ progress and denied them an early victory. The Vauban-designed fortresses of Maubeuge, Longwy and Montmédy also slowed the German advance, allowing the French and British forces to regroup on the river Marne. In November 1918 New Zealanders of General Julian Byng’s British Third Army stormed the Vauban fortress of Le Quesnoy; the Kiwis used scaling ladders in the old fashioned way to oust the German garrison.

Wearied by their losses in World War I, in the 1920s and 1930s the French sought to reconstruct Vauban’s Fence of Iron under the direction of Minister of War André Maginot. His resulting line of fortifications did not prove much of an obstacle, however, when the Germans unleashed their blitzkrieg in May 1940. The Vauban citadel of Lille, on the other hand, put up a stubborn defense. Troops of the French First Army held out in the citadel for four days, defying German attempts to dislodge them using artillery, infantry assault and Junkers Ju 87 dive bombers. The delay provided the French and British armies valuable time to prepare both the defense of the Vauban citadel in Calais and the subsequent evacuation at Dunkirk. In the absence of such fortifications, it is likely Dunkirk would have been an outright defeat for the Allies, rather than bittersweet salvation, with incalculable consequences for the course of the World War II and subsequent European history.

Vauban is rightly regarded as a French hero, with more than 180 forts, citadels and fortresses of his design constructed, improved or planned. He also turned his attention to such civil engineering projects as canals and aqueducts. Vauban’s handiwork is apparent throughout modern-day France, sometimes in fine condition, sometimes rather neglected, although some are now UNESCO World Heritage Sites.

Vauban stressed the necessity to conserve soldiers’ lives, whether in defense or attack. He remains one of history’s pre-eminent military engineers, a man who understood that while no fortress could hold out indefinitely, a well-designed one could buy time for others and, therefore, would be worth the cost of its construction. In more recent times, despite the introduction of rifled artillery and offensive airpower, the value of formal defenses as both a deterrent to a potential aggressor and as a means to delay an invader’s progress remains absolute. Above all, France would have been ruined during the desperate years 1708–11 but for the Fence of Iron, and whenever soldiers and historians think of military engineers, it is likely the name of the provincial nobody who became Marshal Vauban first comes to mind.


For further reading James Falkner recommends his own Marshal Vauban and the Defence of Louis XIV’s France, as well as Vauban’s Fortifications in France, by Paddy Griffith and Peter Dennis, and Soldier of France, by John Hebbert and George A. Rothrock.

Originally published in the September 2012 issue of Military History. To subscribe, click here.