To be privately owned
Holten Castle (Oberhausen)

In Oberhausen, Holten Castle is a moated castle whose origins date back to the 12th century. Once a border defense facility, it now stands as a building of medieval architecture and regional history.
History+
The history of Holten Castle begins with a predecessor building, which was first documented in 1188. In 1307, Count Engelbert II of the Mark had a new border defense system built, which became known as Kastell Holten. Just three years later, in 1310, Holten received town rights under the protection of the castle. The complex and the town became a Cleves fief in 1355 and were pledged to the von Loë family between 1445 and 1557. During the Eighty Years' War, the castle was occupied by Spanish troops in 1586 and 1598.
Source: Wikipedia · Licence: CC BY-SA 4.0
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: 51.5269, 6.7841