The origin of Trebnitz Castle was an extensive, former estate complex, which, in addition to the castle, included the inspector's house, the coach house, the blacksmith's shop with the attached dairy, the laundry room, the wheelwright's shop, the distillery as well as various stable and storage buildings. After an eventful history of ownership, the castle was inherited by the von Brünneck family in 1827. It remained in the family until the Red Army expropriated the last landowner, Harald von Brünneck, in 1945.
The castle in its current form was created through renovation work around 1900. At that time, the two side wings were added to the current central building. The simple manor house was transformed into a stately neo-baroque “castle”. After the castle was transferred to the municipality in 1945, it was used in a variety of ways until 1992: hospital, residential and office building, school, kindergarten and holiday camp. After 1992, the house was extensively renovated with the support of the federal and state governments and was converted into a modern seminar house. Today the castle is home to an international educational institution for children, young people and adults with a German-Polish focus. The Gustav Seitz Museum was set up in the former wash house.