The castle in Osowa Sień was built in 1878 to replace a 18th century manor house. It was built by Eugen Friedrich Heinrich baron von Seherr-Thoss on the request of his wife Anna Julia Teresa who inherited the manor house and who dreamt of a castle with the tallest tower in the area. Still today their initials can be seen on the front door. Only the crowns on top of their initials were destroyed after the War as unsuitable for the new ideology.

During the 1930’ties a general renovation of the castle was made under which the major part of the external stucco was removed and the entire building was painted off-white. This was supposed to give the castle a neogothic or neorenaissance style in line with the historicism that was popular in the area. The wife of the then owner Lothar von Brandenstein, the writer Ruth von Ostau did not want to live in a kitschy castle in Belle Epoque style. She wanted something simple in line with earlier architecture. Now we are trying to return the castle to this style since a return to its original form is almost impossible due to lack of proper documentation as well as financial means.

The major renovation did not omit the interior. The representative parts of the castle were painted in the same off-white color as the exterior.

After the War the castle underwent further changes. It was housing a club, library, café, billiard- and tv room, a dental practice and rooms for the employees. Years later the castle was turned into a school.

All these changes left their mark on the building. In particular a new entrance was built for the school that destroyed the conservatory and two terraces. Since we have good photos of these, we will try to reconstruct them.