Immediately to the left of the staircase is the Stone Room. Between the two doors that lead to the Congress Hall and the Grey Corner Salon hangs a larger-than-life portrait of Empress Maria Theresa (1717–1780) at her coronation as Queen of Bohemia. The Hungarian Crown of St. Stephen on the cushion to the left can nowadays again be seen in Budapest, while the Austrian Archducal Hat is in Klosterneuburg and the Crown of the Holy Roman Empire of the German Nation in the Treasury in Vienna.
Maria Theresa was an archduchess of Austria as well as Queen of Hungary and Bohemia in her own right; however, she only bore the title of "Empress" as the wife of the German Emperor Franz Stefan I of Lorraine.
Opposite, on the side of the room that looks out onto the courtyard is a large black pendulum clock flanked by two female portraits. The Picture on the right shows Wenzel Anton Prince Kaunitz-Rietberg (1711–1794). The picture on the left shows Archduchess Maria Anna (1738–1789), Maria Theresa’s oldest daughter.
The proximity to the clock is no coincidence. From an early age, Maria Anna showed a strong interest in science and the arts, in particular numismatics and mineralogy. Her contemporaries also knew her as an outstanding copperplate engraver and painter. After the death of her mother she moved to Klagenfurt, where she gathered a circle of scholars around her. Owing to a severe illness Maria Anna suffered from breathing difficulties and a deformed spine. As she had a strong inclination toward the monastic life, she became abbess of the Theresian Royal and Imperial Ladies Chapter of the Castle of Prague. However, Klagenfurt remained her residence to the end of her life.