This slender church in the main square owes its name to the marsh where it was built. A grotto at the side of “heldensquare ( Heros’ square) is consecrated to the worship of Our Lady of the marsh. Legend has it that, in the 12th century, a virtuous man was murdered and thrown into this marsh and a woman predicted that a church would be raised on this site.
From that day miracles occurred so the Duke of Brabant, Jean 1, authorised the building of a church. The church (1357- 15th century) was designed by Jan van Oisy and has had several restorations. The cock and the cross on the top were replaced 25 years ago. A peculiarity is that the nave was never built. The façade is supported by two transepts. The recesses in the entrances are beautifully sculpted although they have lost their statues. Inside is a painting by Pieter Josef Verhaegen of Aarschot. The raising of the cross by Niklaas de Backer, 1689, is a copy of one by Jan van Dyck.