At the beginning of the 11th century, Brussels was a port on the river Senne, an ideal trading spot for the primarily farming communities in the area.
At the start of the 13th century, Henry I, Duke of Brabant, came up with the idea of constructing a rampart to protect the wider Brussels area, by the same token asserting his power.
Work on the second set of walls started in 1357 after the town was taken by the troops of Louis II, Count of Flanders, and was completed in 1379.
The first town walls lost their protective function, mainly to avoid hampering the development of the town between the two sets of walls. The grounds on which parts of the walls were located were sold to the State, with the town authorities ordering for the vestiges to be kept in a good state of repair. Over time, all manner of constructions were built against the curtain wall on the inside and the ditch outside the walls was turned into a thoroughfare.
The town continued to grow and thrive beyond the walls with a few suburbs developing all around whilst housing became increasingly dense inside the first set of walls. These were demilitarised in the 16th century and sold to private citizens. The walls subsequently came to serve as a supporting wall for later constructions or as boundaries between plots of land.
The aftermath of the Wars of Religion and the ambitious urban projects brewing prompted the town authorities to sell off some of their lands and to allot another part to improving the public space. This led to gates being dismantled, roads being widened and squares being created. The Treurenberg Gate was demolished in the throes of this urban activity in 1760.
Vast numbers of remnants were preserved until the early part of the 20th century when they came to light during major urbanisation works, but were often destroyed in the process. Since the late 1990s, a protection and preservation policy has been put in place to call a halt to the destruction.
When houses at numbers 8 to 14 rue de Treurenberg were being renovated in 2001, the house abutting the wall collapsed, revealing a large part of this high wall.
At the beginning of the 11th century, Brussels was a port on the river Senne, an ideal trading spot for the neighbouring villages. The first inhabited districts were clustered around the churches of Saint Nicolas, Chapelle and Saint Catherine. The Counts of Leuven, the future Dukes of Brabant, built a castle on Coudenberg hill and a collegiate church dedicated to Saint Michael on the neighbouring hill. The unification of these different areas turned Brussels into a genuine urban entity at the start of the 12th century.
At the beginning of the 13th century, the Duke of Brabant Henry I came up with the idea of constructing a rampart to protect the wider Brussels area, by the same token asserting a symbol of his power. This was to be the first major step in the town's expansion with nearly eighty hectares of land encircled by the walls.
The four kilometre-long rampart encompassed the top and bottom of the town: Coudenberg Castle, the Collegiate Church of St. Michael and St. Gudula, the port of the Senne and the Sint Goriks district up to the Korenmarkt (Cornmarket) district.
The rampart has three components - the wall or curtain wall, the towers and the gates.
The wall, edged on the outside by a ditch, was flanked by some fifty towers and seven gates each with their own drawing bridge: the gates were known as Coudenberg, Steenpoort, Overmolen (or Anderlecht), Saint Catherine, Laken or Black Gate and Saint Gudula or Treurenberg. Visible vestiges and urban traces of the first set of walls can still be seen andwhile the gates may have disappeared, the roads leading into the city still exist today and have often retained the name of the gates they passed through.
The period between 1835 and 1866 represented a major phase in a period of radical transformations in the existing urban fabric. Streets were widened and major thoroughfares created everywhere in the city, starting from the boulevards of the ring towards the old town or, conversely, from the old town to the boulevards.
The North-South junction and the Brussels Central railway station were inaugurated in 1952. Although these works profoundly altered the urban structure of the City of Brussels, the area formed by the Pléban Tower, part of the curtain wall and the foundations of the Treurenberg Gate form a historical symbol of immense value that has been preserved and protected to this very day, courtesy of its specific siting: over time, this area has been totally encompassed and fossilised in an island delimited by four streets: Treurenberg, rue du Bois Sauvage, rue de la Ligne and Place de Louvain. The Treurenberg "island" has always been spared and has survived virtually intact until today. The shape and current outline of this island must be viewed in conjunction with the urban evolution of the district as a whole; bordered on the West by the Cathedral of St. Michael and St. Gudula, the Brussels Central railway station and the city centre, further North by Place des Congrès and the Administrative District, to the East by rue Royale and further South by rue de la Loi and the Royal Park.
Planning project Place Royale and Parc Royal. Start of work on the rue Royale. Place de Louvain enlarged and redesigned.
Start of work on the rue de Ligne. Rue Royale extended and place de Louvain narrowed. Creation of large boulevards at the site of the 2nd city walls.
Creation of the place des Congrès Rue de Ligne extended. Esplanade of the church of St Gudula broadened.
Start of work on the impasse du Parc. Transformation and planning of the Potterie and Isabelle districts. Creation of rue du Gentilhomme. A block entirely redesigned with the creation of the new place de Louvain.
Land register of the City of Brussels. Creation of the boulevard de Berlaimont and demolition of two blocks below the cathedral of St Michael and St Gudula.
The city was accessed through the first set of walls via seven gates, each located at one of the major traffic routes leading to the neighbouring large towns. The gates remained open during the day, serving as toll booths for tax collection, and remained closed at night. Above the cathedral, Saint Gudula Gate, named in honour of its proximity to the collegiate church, had two semi-circular towers projecting outside the walls. The two towers were connected by a straight building with a gable roof pierced by an arched bay closed by two wooden doors and probably a portcullis. A bridge in front of the entrance crossed the moat. In the 16th century the gate was used as a prison and was dubbed Treurenberg (or Treurenborgh) Gate for the first time in 1567 in reference to the wailing of prisoners held there (Treurenberg literally translates as “mountain of tears”). It was destroyed between 1759 and 1761. Treurenberg Gate was in the middle of the street, at number 14. Remnants of the gate's foundations were discovered during work in the 1950s. The inventory of the Historic Monuments of Belgium confirmed the information by dating their discovery in 1952.
Vestiges of the first set of walls remain today, some of which are city monuments and others partial archaeological vestiges inserted in the constructions, all of which have listed monument status, whether visible or invisible. The Treurenberg island stands in an area of cultural, historical and aesthetic interest and is subject to strict heritage regulations. The island is therefore part of a unique architectural gem in Brussels, as it includes the three constituent components of the walls: a tower, a section of curtain wall and the foundations of one of the main gates into Brussels, Treurenberg Gate.