The Gothic chapel is preserved on the second floor of the tower. The tiny room with two bays of the ribbed-cross vault comes probably from the turn of the 15th to 16th century. Cuneiform stone ribs with flute cross each other in mighty platelike keystones and lean on slight pyramidal consoles with moulding-like coverplates. The preserved coats of arms of the Olomouc bishopric and cardinal Dietrichstein on the keystones come from the early 17th century. Relicts of medallions on the walls with scenes from the life of Church Fathers, St. Catharina and Antonius of Padua date back to 1505–1510 and were probably created soon after the completion of the building. Below five front arcs there are figurative scenes: on the eastern wall of the chapel the medallion with the legend of St. Catharina (scene of her decapitation) and most probably the Church Father Ambrosius, on the northern wall probably St. Augustine and Hieronymus, on the western wall a scene with St. Gregorius and the mass of St. Antonius. The paintings were discovered in 1914 by Dr. J. Helfert and their relicts were restored in 1920. However, they are all strongly damaged, the worst the scenes with St. Hieronymus and St. Augustine the lower part of which disappeared with the subsequent breaking through of the late Renaissance portal. The medieval dedication of the chapel is unfortunately unknown. The provenience of the inspiration of the author of painted scenes is supposed to be Lower Austria, the Austrian circle of the so called Vienna master from the last decade of the 15th century; the painter of Brno museum chapel was most probably his successor or disciple.
permises and exhibition