According to legend, an oratory was founded here by Maternus of Cologne (c. 285–315), who also carved a Madonna to replace an earlier pagan idol.

The church does in fact contain a wooden Madonna, albeit from 950 to 1020, but still one of the oldest preserved Marian devotional statues in Western Christianity.

The presence of the Madonna and its allegedly miraculous properties led to the development of the church into a pilgrimage site during the Middle Ages.

According to a local legend, Maternus of Cologne (c. 285–315) was passing through Walcourt during his efforts to Christianise the area and founded an oratory here.

[6][7] Legend recounts how the Madonna was miraculously saved from a fire in 1220, and mysteriously transported by angels and found in the branches of a tree outside the town.

A monastery (abbaye du Jardinet [fr]; destroyed by French revolutionary troops in 1793 and closed in 1796) was founded on the site where the Madonna was rediscovered.

[1] Because most archival sources have been lost, burnt or destroyed in wars, the detailed history of the church is difficult to retrace.

[9] During this period, two of the richest furnishings of the church were also installed, the rood screen (1531) which according to tradition was donated by Emperor Charles V, and the choir stalls (1510–1520).

The 40 seats are made of oak and decorated with misericords, including one which depicts the alleged miracle of the Madonna of Walcourt being transported to safety in a tree when the church was ravaged by fire.