The remains of the Castle can be visited
Altenstein Castle (Ruin)

The Altenstein Ruin, once the ancestral seat of the Barons von Stein zu Altenstein, is on a ridge in the Haßberge mountains in Bavaria. This high castle ruin, located near Maroldsweisach, is considered one of Franconia's largest sites.
History+
The first indirect mention of the castle occurred in 1225, referring to a “Marquard Magnus de antiquo lapide.” Just six years later, in 1231, the complex was directly mentioned as a “castrum” with a church. Altenstein developed into a typical Ganerbenburg, inhabited jointly by several family branches. By 1296, eight families already lived in the fortress. A castle peace treaty from 1441 confirms that ten brothers and cousins from five families had their chambers here. During the Peasants' War in 1525, the castle was damaged. Emperor Charles V granted the Altenstein family high jurisdiction in 1549. After destruction during the Thirty Years' War, the castle began to decay. The von Stein zu Altenstein family left their ancestral castle in 1703 and moved to the newly built castle in Pfaffendorf.
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: 50.1715, 10.7341