Castle complex from the 13th century, two fortifications, both keeps, walls of the former residential apartments, remains of the defensive walls and foundations have been preserved
In former times the so-called Thüringer Pforte, an area near Oldisleben/Sachsenburg where the river Unstrut breaks through the ranges of hills known as Hainleite and Schmücke, was a strategically important point. Here where precious raw materials such as salt, copper and silver were mined nearby an important trade route ran, connecting the southern Harz mountains with the Thuringian Basin.
The safeguarding of this route was necessary and promised to be a lucrative source of income. This was probably one of the reasons why an extensive fortification on the eastern slope of the Hainleite was already erected in pre-early history. According to the present state of research the two stone Sachsenburg castles which are roughly 500 metres apart and whose preserved keeps jut out from the densely wooded countryside, were built between 1250 and 1350 in an area known to have been continuously settled from the early Stone Age to the early Middle Ages.
By cleverly making use of quarrels about the succession of the Thuringian landgrave, Count Siegfried von Anhalt took hold of the area and probably at first ordered a wooden fortification to be built and later the castles of local shelly limestone. There was an unusually frequent succession of owners of these castles; once the buildings were even mortgaged to the City of Erfurt. From the mid-15th century at the latest, when the Lower Sachsenburg was declared an administrative seat and for this purpose was rebuilt as a mansion, the castles had different functions.
The decay of the Lower Sachsenburg started in the late 18th century. Until its decline around 1700 the Upper Sachsenburg continued to serve residential purposes. In the course of the enthusiasm of the late 19th century for medieval castles the already decaying castle was converted into a restaurant for excursionists – in the course of which considerable harm to the medieval building fabric was done. It served this function until 1945.
In this last year of the Second World War both castles suffered considerable damage. It was only in the 1990s that the public took notice of the castle ruins again; in 2002 they became the property of the Palace, Castle and Gardens Trust of Thuringia.
Of the core of the Upper Sachsenburg it is mostly the outer walls of the medieval three-storeyed residential building with chimney as well as the 20-metre high square-shaped keep which have been largely preserved. The ruins of the Lower Sachsenburg are marked by the keep which has been preserved up to a height of 22 metres.