The Kaunitz Era
The building on Ballhausplatz enjoyed its first golden age under Wenzel Anton Prince Kaunitz-Rietberg (1711–1794). Court and State Chancellor from 1753 to 1792, Kaunitz was a leading proponent of the reform of the state under Maria Theresa (1717–1780) and Joseph II: His reorganisation of the civil service resulted in a centralisation of the hitherto fragmented state administration.
The first major alteration to the building took place in the Kaunitz era. When Maria Theresa had the archives from Graz, Innsbruck and Prague brought to Vienna as part of the centralisation process, the building had to be extended to make room for these collections. Kaunitz took a lively interest in the reconstruction work carried out between 1764 and 1767 by the court architect Nicolaus Franz Pacassi (1716–1790). As Kaunitz had a strong dislike of bright light he immediately reserved the darkest rooms in the building for himself.