Tardos red limestone is one of the finest materials in Hungarian art history and architecture; due to its polishability and color, it was considered equivalent to genuine marble in the Middle Ages. This material, a favorite of King Matthias’s Renaissance court, can also be found in the Károlyi Palace in the Palace District, built at the Turn of the Century, where the restoration work was carried out by Vivien, a colleague skilled in both architectural sculpture and stone restoration.