The Citadel

The Citadel of Diest is the only remaining brick example in Flanders. The citadel was built on the 'Allerheiligenberg', (All Saints’ Hill) between 1845 and 1853. The construction of the Citadel was the dominant conclusion of the transformation of Diest into a fortified city, after the earlier building of the fort, the ramparts and the city gates. The entire structure is purely focused on military functionality, with the bluestone gateway in neoclassical style as its only embellishment.

The complex served as an independent reinforcement that could stand its ground autonomously during a siege or even after the fall of the city. Moreover, it also had to use cannonry to prevent the enemy from leaving the city to advance on Leuven.

Though the threat generated by the Netherlands quickly disappeared, until recently the Citadel still maintained various military functions. The First Battalion of Paratroopers was stationed at the Citadel until 2011. Following their relocation, the complex became vacant. Today the site gravitates between past and future ... and is searching for a new purpose.


The Citadel was built in the shape of a pentagon (each side approx. 190 metres) and is encircled by dry moats. In the middle, it has a large open square where arched passageways run to the front lines and bastions. The barracks were equipped with various facilities to provide for the needs of the troops. These facilities included active service rooms, living and sleeping quarters, storage rooms for armaments and food, a pharmacy and doctor's office, a bakery and kitchen.

A unique element is the Chasseloup-Laubat defence system.
The cannons in the flanks of the bastions (pentagonal protrusions of the rampart) were to flank the moats. Here, the cannon cellars are protected by a frontal brick mask. It not only provided a solution for smoke discharge, but also prevented the cannons from being destroyed. The Diest Citadel is the only one in Europe where this defence system has remained almost intact.

A guided visit to the Citadel and/or the Pegasus museum is possible. More information on the tab ‘For Groups’.