The casemates of Luxembourg: history, myths and legends

Understanding the casemates

To begin our analysis and before going into the historical context, it is essential to understand what casemates are and their functions. Well, casemates were fortified defensive structures that were generally located underground or protected by thick walls and were designed to resist enemy attacks, especially artillery bombardments.  Below we will examine some of their main characteristics:

Advanced engineering

Their construction required advanced knowledge in military architecture and engineering and was the work of experts. They were built with thick stone or brick walls and vaulted ceilings, designed to withstand the impact of shells and provide a safe shelter in times of war.

Strategic location

They were located at key points within fortifications such as bastions or ramparts and were often connected by subway tunnels to facilitate the movement of troops and supplies.

Gun ports or embrasures

They featured openings specifically designed to fire cannons or small arms and offered optimal angles of attack without exposing defenders to enemy fire.

Multipurpose

In addition to housing artillery, casemates were used to store ammunition, to shelter troops or even to protect the civilian population during bombardments.

Adaptation to the terrain

Many casemates were designed to blend into the natural landscape and take advantage of geographical features to enhance their defensive effectiveness.

Underground connections

In many cases, they were part of a network of interconnected subway tunnels allowing discreet and protected movements even during fighting.

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Historical context and origin of the casemates in Luxembourg

There are two casemates in Luxembourg city, those of the Pétrusse and those of the Bock, both constructions are a huge system of vaults and subway tunnels that were part of the defences of the city. They date from the seventeenth and eighteenth centuries and occupied an area of more than 17 kilometres.

Luxembourg's casemates are full of mystery, if they could speak, they would tell grim tales of the days when Luxembourg was one of the most envied fortresses in Europe. The defensive system spanned several floors and included galleries dug up to 40 m deep. Because of these impressive bastions, Luxembourg City was rightly nicknamed “Gibraltar of the North”.

In 1867 the fortress was evacuated and had to be dismantled after the neutralization of Luxembourg. The dismantling took 16 years and the casemates were reduced to 17 km. Due to their subway location in the city, the network could never be destroyed.

When the casemates lost their military use, they were reused in various ways. During the two world wars, the Casemates du Bock and those of the Pétrusse valley served as an opening and were able to protect 35,000 people in case of alert or bombardment. In 1994, the Bock and Pétrusse casemates became a UNESCO World Heritage Site and are now open to the public.

Luxembourg Pétrusse casemates

The origin of these subterranean passages dates back to 1644 when the Spanish modernized the medieval works and built large bastions such as the Beck Bastion whose platform occupies the Constitution Square and where the Gëlle Fra memorial stands. Under this bastion are the subterranean tunnels known as the Petrusse casemates.

The fortification of this bastion and the construction of the subterranean tunnels took place in several stages, let's look at them one by one:

The casemates were standing until 1867 when the neutralization of Luxembourg took place and the fortress was dismantled together with the casemates. After the dismantling, some 17 km of casemates remained and over the decades the casemates were used for various purposes. Finally, the Pétrusse Casemates took on a touristic role and were opened to the public in 1933.

Luxembourg Bock casemates

The rocky promontory on a meander of the Alzette known as Bock or “Bouc” since the late Middle Ages is an ideal place for fortification and can be considered the birthplace of the city of Luxembourg.  Around 963 Count Sigefroid acquired from the Abbey of Saint-Maximin of Trier a small steep piece of land, a kind of rocky promontory on which stood a small fortress, probably erected in Roman times and known as “Lucilinburhuc”, which meant “small fortified castle”.

Sigefroi soon had a larger castle built here, around which grew the town of Lucilinburhuc, which became the centre of a small but important state of great strategic value to France, Germany, and the Netherlands.As the dynasty of the counts and then dukes of Luxembourg gained importance the castle was enlarged, unfortunately, it was badly damaged by the wars of the 16th century and was replaced by more modern fortifications.

In 1745 the Austrians began to build the casemates in the Bock rock. These tunnels covered an area of 1,100 m² and could accommodate a garrison of 1,200 soldiers with their equipment and about fifty cannons. These works, together with the casemates of the Petrusse, would make the city one of the most important strongholds in Europe.

Like the Pétrusse casemates, the Bock casemates were dismantled in 1867 when the neutralization of Luxembourg took place, they also took on a tourist role and were opened to the public in 1933, at the same time as the Pétrusse casemates.

The extraordinary network of subway galleries of the Pétrusse and the Bock are now one of the main attractions of the city. There it is possible to immerse oneself in the incredible history of the country and the important role played by the casemates that could house not only thousands of defenders, their equipment, and horses, but also artillery and armament workshops, kitchens, bakeries, slaughterhouses and other infrastructures.

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