The Franciscan Monastery of St. Bernard was founded in 1451 during his second stay in Brno by the Italian Franciscan friar and passionate preacher John Capistrano. A site was purchased for the monastery in front of the city walls in the south below Puhlík by the mill embankment. During the first Swedish siege in 1643, the commander of Brno, Colonel Schönkirch, had the Franciscan monastery set on fire for strategic reasons, and it burnt down together with the church of St. Bernard. The Franciscans relocated to the city and in compensation for the destroyed property they received from the city council the church of St. Mary Magdalene and four Gothic houses, on the site of which the monastery convent was completed in 1654.
Under the eastern wing of the monastery and partly under the two-storey street building, as well as under the square, there are extensive cellar spaces of several levels and complex layouts. Only parts of the rubble stone masonry survive from the former Romanesque building. In the upper part, the Gothic masonry was also removed, probably during the construction of the monastery, and replaced by Baroque walls with vaults. To this day, the full extent of the historic underground has not been explored.
In September 1982 the vault in the connecting corridors under the square was broken. During garbage collection, the pavement above the collapsed vault of two floors of the underground corridors fell under a truck. The accident was dealt with by concreting over these areas in a time-sensitive manner. The extensive cellars under the monastery building were modified and partly structurally secured in the 1980s in a very unconceptual way. Today, the underground and the whole building are in a very poor state and only timely repair and appropriate use will lead to the rescue of these very attractive historical sites of the once so popular and romantic Roman Square.