The remains of the Castle can be visited
Hanstein Castle

The Hanstein Castle Ruin, one of the largest of its kind in Central Germany, stands near Bornhagen in the Thuringian district of Eichsfeld. Its strategic location near the tri-border area of Thuringia, Lower Saxony, and Hesse makes it a testament to bygone eras.
History+
The first confirmed mention of Hanstein Castle occurred in 1070 when it was destroyed by Henry IV. At that time, it belonged to Count Otto of Northeim and must have been built some years prior. After the extinction of the Northeim counts in 1144, the castle passed into Welf possession. In 1209, it came into the hands of the Archbishop of Mainz, who in 1308 commissioned Heinrich and Lippold von Hanstein to build the current complex. The Hanstein family used the castle as a border fortress and expanded their possessions in the 14th and 15th centuries, leading to the formation of the noble court of Hanstein. As they were denied the acquisition of town sovereignty, the Lords of Hanstein at times resorted to robber knighthood.
Source: Wikipedia · Licence: CC BY-SA 4.0 · Image: Roland Neubert, Halle (Saale)
This description draws on the facts documented in the linked Wikipedia article; Wikipedia content is licensed under CC BY-SA 4.0. Wording and editing: Mobile History.
Location: 51.3394, 9.9400