Developed around an elevated mound, Mons was for many years the main fortress of the Hainaut counts. The oldest building of the group, probably replacing motte earthworks located by recent excavations, housed the entrance to the castle, on the ground floor, with a chapel on the upper level. Within this configuration that is frequent in fortifications prior to the 13th century, the chapel is distinguished by the remains of Romanesque frescoes, replaced by copies.
Sources mention a reworking of the fortress at the end of the 12th century. The end of the 13th century saw a second phase of redevelopment works at the fortress corresponding to part of the walls and the Caesar tower, as well as another tower uncovered by the excavations. Entrance to the site was then more substantial, with a portcullis and appropriate defences. At this time, the walls of the counts' castle were included in the town's defences, without direct access to the outside.
Gradually losing its military function, the keep was dismantled under archduke and archduchess Albert and Isabelle. The castle of the counts, replaced visually by the belfry, built not far away in the 17th century, retained its use as an administrative centre until the end of the 18th century, before being converted into a hospice. The end of the 19th century saw the destruction of the walls and the transformation of the surrounding area into a country park. It was only from 1984 onwards that restoration works and archaeological excavations began.
Exceptional heritage site of Wallonia