Hibernating a palace

A series of coincidences made Schloss Eggenberg the unique synthesis of art that it is today. Built in the 17th century to serve one of the most powerful politicians at that time as a prestigious residence during the Thirty Years War, it still hosted an imperial wedding under the critical eyes of Europe in 1673. The grandeur and wealth of the Schloss were the source of general admiration. Only a few decades later, in 1717, the last Prince of Eggenberg – a boy of 13 years – died from appendicitis. And things started going downhill from that time on. Under the strict rules of the time, his mother, who was largely excluded from social life through her early widowhood, had also drifted into ruinous legal proceedings over the Bohemian inheritance of the family. As a result, the remaining assets of the family, which had been one of the richest in the Empire only a few decades before, were lost. Up to her death in 1754, the Schloss had not only fallen into disuse for decades, but also lost the most precious parts of its appointments and furnishings. Only the ceiling paintings in their luxuriant stucco frames have been preserved throughout the second floor.

When Maria Eleonora, the oldest sister of the last Prince, and her husband, Count Herberstein, finally inherited the Schloss, it was no longer habitable for their purposes. The two began to furnish the interiors in the Rococo style. While the ceilings and the Planetary Room remained unaffected by this development, the walls of the 24 state rooms were covered with silk damask or large-format murals from 1754 onwards. Each room was appointed with faience stoves; new furniture was commissioned; three East Asian cabinets were added and the Schloss church was attached.

But the Eggenberg-Herberstein couple remained childless. A branch of the Herberstein family, resident in Silesia, finally inherited the Schloss and garden in 1789 and only used it for a few weeks a year over the next 150 years. The entire piano nobile remained virtually unchanged. On request, selected guests could visit the Schloss as a “national monument” under the watchful eye of the “castellan”. Even highly honourable requests to rent the property – for example, by the widow of the murdered French heir to the throne, the Duchess of Berry, then living in exile in Styria, who would very much have liked to acquire Schloss Eggenberg as her summer home – were rejected. Schloss Eggenberg became a romantic country palace where the remote owner indulged in his passion for fashionable landscape garden designs. Nobody lived in the piano nobile on the second floor, and it was not heated for over 100 years.

After the Schloss was sold to the Reichsgau Steiermark in 1939, the war prevented major changes. Extensive restoration and the final transfer of the building to the responsibility of the Landesmuseum Joanneum followed after World War II.

In the 1950s and 1960s, there was considerable support for plans to modernise the state rooms, and to open and use them for official Styrian receptions. But in contrast to many other historic interiors in Europe, Eggenberg was spared from interference and (subsequent) damage due to heating and electrical installations. There simply wasn’t the cash required – a good thing, from today's perspective. The unique value of the ensemble was recognised later on, when the decision was taken deliberately not to add modern installations to the piano nobile. Thus a unique, almost unadulterated spatial artwork has been preserved, one which we want to bequeath unaltered to the next generations.

If the rooms had continuously been heated over the centuries, the ceiling paintings would have long been lost due to the temperature difference between the interiors and the attic above. This is also why comparable cycles of oil paintings on the walls are not preserved to this extent anywhere else. The other appointments of the rooms with their sensitive organic materials (wood and textiles) would have been ill-equipped to survive climatic fluctuations, since the latter are a main reason for serious damage and aging.

Building fabric and appointments respond to rapid climate changes (the increase or decrease of temperature) by absorbing or releasing moisture from and to the ambient air. Warm air can hold more moisture than cold air. When air has cooled down to the extent that it can absorb no more steam, moisture condenses on the coldest surface, a phenomenon that can easily be observed on car windscreens. Very often, however, the most polluted areas in the interiors are the windows (panes and wooden frames), or the ceilings in the state rooms, because they are only separated from the cold attic by a raft of ceiling beams. At the same time, the steam-blocking layer of oil paintings is the condensed surface (dew point)

What’s more, all other organic surfaces act as a moisture buffer for the air in the room: when it cools and therefore absorbs less steam, the surplus steam penetrates wood or textile substances, causing them to swell. If the room is warmed by heating, the process goes in the other direction. Wood dries out and “tears”, a phenomenon that can also be seen in one’s own home.

For historical materials, this sequence of expansion and contraction processes results in plenty of stress factors with serious consequences:

• the layers of the coloured finish peel off due to stress or steam pressure
• the microstructure becomes loose
• wooden parts burst
• the bindings of the coloured finish are lost through binder softening
• moisturising of building components or wall-bound appointments
• consequent infestation by microorganisms (mould)
• mobilisation of salts

These processes mutually reinforce themselves in their harmful effect, resulting in rapidly progressive aging and destruction of the building fabric. This is why all museums are so concerned about their ambient conditions. Best possible stable humidity and slow drying processes ensure the conservation of the building fabric and its long-term preservation. But because air-conditioning cannot be installed in the state rooms without destroying them at the same time, we follow a pattern that has been established for centuries, which is to allow them the time to adapt slowly to natural changes.

This is why at Schloss Eggenberg the season still ends on October 31. The shutters of the 52 windows are closed. They protect against cold, heavy rain and snow storms. The interiors cool down very slowly in accordance with the outdoor climate until the inside temperatures reach their low-point in February. All materials can slowly adapt to this process without incurring damage, as evidenced by the history of the structure. Climate curve performance is amazingly stable, even calmer and flatter than the climate curves of an ideally adjusted air conditioning system.

We gladly accept this restriction in the use of space in the interests of long-term conservation and also find that our visitors tend to agree with us. Not everything is usable, accessible and marketable for everyone at all times. Monuments are values per se. They have a non-consumable aspect which a civilized society is duty-bound to respect. Conservation and preservation also means restriction to a large extent.

While precious objects are presented in glass cabinets during an exhibition to protect them from mechanical and climatic damage, this measure is not possible at a monument such as Schloss Eggenberg. Its particular value resides in the immediate experience of another time. Our visitors are given the rare opportunity to experience historic interiors without modern interventions, without Plexiglas panels in front of the walls, without glass falling on porcelain objects and without cordoning off the furniture. Only a few historic homes offer this unique experience.