Only few sources from the time the Sommerpalais was built are available today. It is nonetheless certain that the architectural elements originate from the late 1770s. A memorial plaque from June 1, 1779 states: »Der regierende Fürst Heinrich XI. läßt das Sommerpalais ausbauen und mit Stuckarbeiten, Tapeten etc. schmücken« (The ruling Prince Heinrich XI has the Sommerpalais adorned with stucco, wallpapers etc.).
Heinrich XI Reuss Elder line became imperial prince in 1778. He might have taken this event as a reason to change the interior decoration of the existing residence, so that it suited his position as sovereign.
While the interior decoration is from the late 1770s, the inner architecture in the ground floor shows that the building must be older. It dates back to the years 1768 and 1769. In 1768 Heinrich XI Reuss became heir to the House of Reuss Elder line and therefore built a new summer residence. Maps and etchings from an earlier date show that there had previously been another three-wing building at the same location.
The Prince was a well-travelled man and open-minded in terms of sciences and art. Although at first he had a more conservative new building in mind, he yet decided to model it on French architecture. He thereby once again showed that he preferred the international architecture of his time. Thus, the Sommerpalais is a very early example of neo-classicism in central Germany.
The main façade faces south. The inscription on the central gable shows the Reuss coat of arms with the princely crown and a banner saying: »Maison de belle retraite« (house of refuge).
Three steps lead to the Garden Salon, the former orangery. In the 18th and 19th century it was also used for parties, concerts and theatrical performances. Nowadays, the Staatliche Bücher- und Kupferstichsammlung holds exhibitions and puts on concerts in there. This impressive room is 36 metres long and seven metres wide. Its ceiling is supported by two pillars. The stucco was applied in 1782/83. Reliefs of garden tools, theatrical props and musical instruments indicate the room’s double use. On a cast-iron plaque in the fireplace, facing the main entrance, is a depiction of the Reuss coat of arms with the princely crown and the date 1783. Doors off to the left and the right lead to the actual entrance of the museum, through the staircase from the early 20th century to the Beletage on the first floor.
The south facing staterooms comprise of the ceremonial hall along a single axis with cabinets and antechambers on left and right. The height of the ceremonial hall reaches into the upper floor; it, and the rooms connected to it, are richly decorated with stucco. Overdoors are decorated with garlands and putti (allegories of sculpture and painting in the west cabinets, allegories of farming and breeding in the east cabinet). The cast-iron plaques in the fireplaces bear the initials of Heinrich XI, the Reuss coat of arms and the date 1769.
The rooms facing north are all smaller than those on the south – among them are the Chinese Room, the prince’s bedroom and the dining room, now containing representative books from the historical library. In the mezzanine, the former living quarters, there are the library, a reading room and the restoration workshop.
The Reuss family removed their movable belongings when they left the Sommerpalais. The furniture you see today is part of the first museum decoration from the 1920s. Some of the furnishings are reproductions from the 1990s.
The Sommerpalais is located in the historical park of Greiz. It has been in ownership of the Stiftung Thüringer Schlösser und Gärten since 1994. The foundation was responsible for the thorough renovation from 2005 to 2011.