In 1324, the Muthaus (Moshus = palas) was built by Conrad and Louis of Rosdorf and the place was expanded into large castle complex.

The Muthaus has a height of 35 metres and is probably the oldest, fully surviving secular building in southern Lower Saxony.

In 1380, it was the seat of government for the Welf duke after he had been driven out of Göttingen; he died here on 13 December 1394.

From 1725 to 1780 major remodelling work was carried out on the castle in order to turn it into domestic buildings for the future estate (Domäne).

In 1972 the estate and castle site were sold to the town of Hardegsen, who then rented it out.