Ziesar has an exceptionally well-preserved medieval castle, which served as the residence of the bishops of Brandenburg from the middle of the 14th century to the middle of the 16th century. The Reformation marked the end of the episcopal residence in Ziesar. The administration of the office remained at the castle until 1819, after which it became private property until it was nationalised after the end of the war in 1945. From the middle of the fifties until the nineties, learning took place within the medieval castle walls, which housed a boarding school. Some time later, at the turn of the millennium, the reconstruction of the present museum and the restoration of the castle chapel began. It has a magnificent brick façade from 1470 and is completely painted around 1500. The southern façade of the chapel has high windows and the northern side has no windows, which is due to the defensive character of the castle in the Middle Ages.
In the castle museum of the Brandenburg church and cultural history of the Middle Ages with the permanent exhibition "Wege in die Himmelsstadt. Bischof-Glaube-Herrschaft (800-1550)", spectacular medieval finds can be seen, including tracery and curtain paintings and two medieval underfloor heating systems. Furthermore, the exhibition on more than 1000 square metres illustrates the history of the castle in Ziesar in its different epochs and focuses on the multi-layered architecture and use in the different periods.
In the castle museum of the Brandenburg church and cultural history of the Middle Ages with the permanent exhibition "Wege in die Himmelsstadt. Bischof-Glaube-Herrschaft (800-1550)", spectacular medieval finds can be seen, including tracery and curtain paintings and two medieval underfloor heating systems. Furthermore, the exhibition on more than 1000 square metres illustrates the history of the castle in Ziesar in its different epochs and focuses on the multi-layered architecture and use in the different periods.