The cathedral's origins are obscure, but historians agree that, as early as the 9th century, a chapel dedicated to Saint Michael probably stood in its place, on what was the most important point of Brussels at the time; the crossroads of two major trade routes—a first one connecting the County of Flanders and Cologne, and another between Antwerp and Mons, then France.

These crossroads were located on the Treurenberg hill (French: Mont des pleurs; "Mount of sorrows"), where the St. Gudula Gate stood (integrated in the first city walls), and which was later used as an ominously famous prison, hence its name.

[8] On 6 June 1579, the collegiate church was pillaged and wrecked by Protestant Geuzen ("Beggars"), and Saint Gudula's relics were disinterred and scattered.

It was not until 1962, with the creation of the Archdiocese of Mechelen–Brussels, that the collegiate church was promoted to the rank of co-cathedral, when it became the Archbishop's seat, together with St. Rumbold's Cathedral in Mechelen.

Restoration work was carried out in the 19th century under the direction of the architect Tilman-François Suys who, from 1839 to 1845, restored the towers and portals,[10] and again in the 20th century under the direction of Jean Rombaux, then Victor Gaston Martiny, chief architect-town planner of the Province of Brabant and member of the Royal Committee for Monuments and Sites.

[9] On those occasions, archaeological excavations were undertaken, which led to the discovery of remains of the Romanesque church and crypt underneath the current choir.

The building adopts the classic plan: a Latin cross with a three-bay long choir ending in a five-sided apse surrounded by an ambulatory.

The whole structure is supported by sturdy flying buttresses with double spans, influenced by Soissons Cathedral, crowned by pinnacles and gargoyles.

Furthermore, the façade is divided horizontally into three levels: a lower one entirely centred on the three portals; a median one opened by the large multi-light window flanked by two high three-light windows, each inscribed in the axis of one of the towers; and an upper one characterised by the large triangular tympanum which, developing from a gallery with fine columns, is topped by several flaming pinnacles, of which the central, more imposing, reaches a height of 55 metres (180 ft).

These statues date from the 17th century and were created by Lucas Faydherbe, Jerôme Duquesnoy the Younger, Johannes van Mildert and Tobias de Lelis, all renowned sculptors of their time.

[7] To the right of the portal of the northern transept is an elegant 17th-century sculpture depicting The education of the Holy Virgin by Saint Anna by Jerôme Duquesnoy the Younger after a painting by Rubens.

The cathedral also contains the unmarked burial place of Dermot O'Mallun, the last Irish-born chief of the name of the O'Moloney sept of Thomond.

It also contains the mausoleums of the Dukes of Brabant and Archduke Ernest of Austria made by Robert Colyn de Nole in the 17th century.

Jean Micault, receiver general of Charles V, and his wife, Livine Cats van Welle, were buried there, and an altarpiece, probably commissioned by their son Nicolas, was dedicated to them.

Right of the choir is the Chapel of Our Lady of Deliverance (1649–1655), which was built in a late Gothic style and contains a Baroque altar by Jan Voorspoel (1666).

The northern window dates from 1537 and represents Charles V and his wife Isabella of Portugal in adoration for the Holy Sacrament and accompanied by their patron saints Charlemagne and Elizabeth of Hungary.

Also worth mentioning are the impressive series of fifteen stained glass windows from the 19th century in the aisles, produced by Jean-Baptiste Capronnier.

This instrument is the work of the German organ-builder Gerhard Grenzing, based in Barcelona, in collaboration with the English architect Simon Platt.

The north tower contains a single bourdon called Salvator, it was cast by Peter van den Gheyn in 1638.

At the end of the 1990s, local ornithologists discovered a couple of peregrine falcons roosting on top of the cathedral's towers.

As a result of watching the three chicks perform acrobatic feats on the cathedral's gargoyles, at the end of May 2004, the project "Falcons for everyone" was developed by the RBINS in association with the Commission Ornithologique de Watermael-Boitsfort.

Other official ceremonies organised in the cathedral include the Te Deum on Belgian National Day, attended by the king and other dignitaries.