The Fortress of Luxembourg (Luxembourgish: Festung Lëtzebuerg; French: Forteresse de Luxembourg; German: Festung Luxemburg) is the former fortifications of Luxembourg City, the capital of the Grand Duchy of Luxembourg, which were mostly dismantled beginning in 1867. The fortress was of great strategic importance for the control of the Left Bank of the Rhine, the Low Countries, and the border area between France and Germany.
The fortifications were built gradually over nine centuries, from soon after the city's foundation in the tenth century until 1867. By the end of the Renaissance, Luxembourg was already one of Europe's strongest fortresses, but it was the period of great construction in the 17th and 18th centuries that gave it its fearsome reputation. Due to its strategic location, it became caught up in Europe-wide conflicts between the major powers such as the Habsburg–Valois wars, the War of the Reunions, and the French Revolutionary Wars, and underwent changes in ownership, sieges, and major alterations, as each new occupier—the Burgundians, French, Austrian and Spanish Habsburgs, and Prussians—made their own improvements and additions.
Luxembourg took pride in the flattering historical epithet of the "Gibraltar of the North" as a result of its alleged impregnability. By 1443 it had only been taken by surprise by Philip the Good. In 1795, the city, expecting imminent defeat and for fear of the following pillages and massacres, surrendered after a seven-month blockade and siege by the French, with most of its walls still unbreached. On this occasion, advocating to extend the revolutionary wars across the French borders, the French politician and engineer Lazare Carnot explained to the French National Convention that in taking Luxembourg, France had deprived its enemies of "... the best fortress in Europe after Gibraltar, and the most dangerous for France", which had put any French movement across the border at a risk.Kreins, Jean-Marie. Histoire du Luxembourg. 3rd edition. Paris: Presses Universitaires de France, 2003. . p. 64. Thus, the surrender of Luxembourg made it possible for France to take control of the southern parts of the Low Countries and to annex them to her territory.
The city's great significance for the frontier between the Second French Empire and the German Confederation led to the 1866 Luxembourg Crisis, almost resulting in a war between France and Prussia over possession of the German Confederation's main western fortress. The 1867 Treaty of London required Luxembourg's fortress to be torn down and for Luxembourg to be placed in perpetual neutrality, signalling the end of the city's use as a military site. Since then, the remains of the fortifications have become a major tourist attraction for the city. In 1994, the fortress remains and the city's old quarter were listed as a UNESCO World Heritage Site.
History
From Roman fortification to medieval castle In Roman times, two roads crossed on the plateau above the Alzette and Pétrusse rivers, one from Arlon to Trier, and another leading to Thionville. A circular wooden palisade was built around this crossing, which could provide protection to the farmers of the region in case of danger. Not far from this, on the Bock promontory, was the small Roman fortification Lucilinburhuc – this name later turned into Lützelburg, and later still into Luxembourg.
After the Romans had left, the fortification fell into disrepair, until in 963 Count Siegfried of the House of Ardennes acquired the land in exchange for his territories in Feulen near Ettelbrück from St. Maximin's Abbey in Trier. He built a small castle on the Bock promontory, which was connected to the plateau through a drawbridge. In time, a settlement grew on the plateau. Knights and soldiers were billeted here on the rocky outcrop, while artisans and traders settled in the area beneath it, creating the long-standing social distinction between the upper and the lower city. The settlement had grown to a city by the 12th century, when it was protected by a city wall adjacent to the current Rue du Fossé. In the 14th century, a second city wall was built, which also incorporated the land of the Rham Plateau. A third wall later incorporated the urban area as far as today's Boulevard Royal.
Development and use as fortress The reinforcement of the fortifications which had begun in 1320 under John the Blind continued until the end of the 14th century. In 1443 Philip the Good and his Burgundian troops took the city in a surprise attack by night. This started a period of foreign rule for Luxembourg, which had been elevated from a County to a Duchy in 1354 by Charles IV. Integrated into the territory of the Netherlands, it would be drawn into the duel between Valois-Bourbons and Habsburgs over the next few centuries, and was ruled by the Burgundians, the French, and the Spanish and Austrian Habsburgs. During this time the fortress was continually expanded and extended, and adapted to the military requirements of the day. The casemates, constructed by the Spanish and Austrians, are of particular note.
By marriage, the fortress passed in 1447 to the Austrian Habsburgs along with all Burgundian possessions. In 1542, the French troops of Francis I took the fortress, which was soon retaken by troops of the Holy Roman Empire. Around 1545, Italian and Dutch engineers under Holy Roman Emperor Charles V built the first bastions, linked by curtain walls, on the site of the current Boulevard Roosevelt and Boulevard Royal. The ditch was enlarged from 13 to 31 metres. Ravelins were also added.
Spanish rule
Later, when the Spanish occupied the city, the aggressive policy of French King Louis XIV from 1670 led to the construction of additional fortifications. With a French attack seeming imminent, the Spanish engineer Louvigny constructed several fortified towers in front of the glacis from 1672, such as the Peter, Louvigny, Marie and Berlaimont redoubts; he also built the first barracks in the city. This formed a second line of defence around the city. Louvigny also considered constructing works on the other side of the Pétrusse and Alzette valleys, but the Spaniards lacked the funds for this. He had, however, anticipated what the French would do after 1684.
French siege and expansion under Vauban
After the successful siege by Louis XIV in 1683-1684, French troops retook the fortress under the renowned commander and military engineer Sébastien Le Prestre de Vauban. From 1684 to 1688, Vauban immediately started a massive re-building and expansion project for the fortifications, using more than 3,000 men. Advance fortifications were placed on the heights around the city: the crownwork on Niedergrünewald, the hornwork on Obergrünewald, the "Corniche de Verlorenkost", Fort Bourbon and several redoubts. He greatly expanded the military's hold over the urban space by integrating Pfaffenthal into the defences, and large barracks were built on the Rham and Saint-Esprit plateaux. After the War of the Spanish Succession and the Peace of Ryswick, the fortress came under Spanish control from 1698, then passed to French administration again in 1701.
Austrian period In 1713 the Treaty of Utrecht gave Luxembourg to the Dutch, who ruled there for two more years before the fortress was retaken by Austrian troops in 1715, who remained in possession almost for the rest of the century. The fortress of Luxembourg now formed one of the main strategic pillars in the defence of the Austrian Netherlands against French expansion. For this reason, Vauban's fortifications were reinforced and extended. It was under Charles VI and Maria Theresa that the fortress expanded the most in terms of surface area: the Austrian engineers added lunettes and several exterior forts (Olizy, Thüngen, Rubamprez, Rumigny, Neipperg, Wallis, Rheinsheim, Charles), closed off the valley with locks, and dug nearly 25 km of casemates into the bedrock. The fortress now had a triple line of defences on all sides.
The Austrian engineer Simon De Bauffe was responsible for planning and carrying out this greatest expansion in the history of the fortress.
French Revolution and Prussian garrison
After an 11-month blockade, the city of Luxembourg was taken by French Revolutionary troops in 1795. Subsequently, the Duchy of Luxembourg was integrated into the French Republic and later the French Empire as the "Département des Forêts". In the aftermath of Napoleon's final defeat in 1815, the Congress of Vienna elevated Luxembourg to a Grand Duchy, now ruled in personal union by the King of the Netherlands. Simultaneously, Luxembourg became a member of the German Confederation, and the fortress became a "federal fortress". To this end, the Dutch King-Grand Duke agreed to share responsibility for the fortress with Prussia, one of two major German powers. While the Dutch King remained fully sovereign, Prussia received the right to appoint the fortress governor. The garrison would be made up of one-quarter Dutch troops and three-quarters Prussian troops.Engelhardt, Friedrich Wilhelm. Geschichte der Stadt und Festung Luxemburg: Seit ihrer ersten Entstehung bis auf unsere Tage. Luxembourg: Rehm, 1830. p. 284-285 As a result, until 1867, around 4,000 Prussian officers, NCOs and men were stationed amongst a community of about 10,000 civilian residents. Notably, the fortress had already been garrisoned by Prussia since 8 July 1814, before the Congress of Vienna.Carmes, Alex. "Die Zusammensetzung der Garnison" (in German). In: Musée d'Histoire de la Ville de Luxembourg (ed.). Das Leben in der Bundesfestung Luxemburg (1815-1867). Luxembourg: Imprimerie Centrale, 1993. pp. 87ff
The Prussians modernised the existing defences and added yet more advance forts, Fort Wedell and Fort Dumoulin. There were even plans to build a fourth line of defences several kilometres from the city, to keep potential attackers even further at bay. However, this was never implemented due to the demolition of the fortress in 1867 (see below).
Officially, the Prussian garrison in Luxembourg operated as an instrument of the German Confederation. Yet since Austria, the other major German power, had given up its possessions in the Low Countries, and Prussia had taken over the defence of the Western German states, Prussia's interests significantly overlapped with those of the Confederation. Prussia was also able to defend its own geopolitical interests at the same time. The timeline of its occupation of the fortress underscores this: Prussia occupied the Luxembourg Fortress from 8 July 1814, before the Congress of Vienna had declared it a federal fortress on 9 June 1815, and before the Confederation even existed. Only after 11 years of the Prussian garrison was the fortress formally taken over by the Confederation on 13 March 1826. Similarly, although the Confederation dissolved in 1866, Prussian troops did not leave the fortress until 9 September 1867. Whether it was a federal fortress or not, Luxembourg was "the most Westerly bulwark of Prussia".
According to the military convention signed in Frankfurt am Main on 8 November 1816 between the Kings of the Netherlands and of Prussia, the Fortress of Luxembourg was to be garrisoned by 1/4 Dutch troops and 3/4 Prussian troops. Article 9 stipulated that, in times of peace, the garrison should number 6,000 men, though this was temporarily lowered to 4,000 as the Allies were occupying France. In practice, the level of 6,000 men was never reached.
In fact, the garrison consisted exclusively of Prussian troops: the Netherlands never provided their one-quarter of the garrison. Later, the Luxembourg-Prussian Treaty of 17 November 1856 gave Prussia the exclusive right to garrison troops in Luxembourg.