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

In the Lahn-Dill district, the Philippstein Ruin, a former spur castle, is located above the eponymous village. Its history is linked to the safeguarding of territory and mining.
History+
The construction of Philippstein Castle took place in 1390 under Count Philipp I of Nassau-Weilburg. Its purpose was to secure the comital territory and the mining operations in the region. By the 16th century, the complex lost its strategic importance and fell into disrepair after the last administrator departed. In the 19th century, the ruin served as a quarry for the villagers, with sections dismantled and the stones used for new constructions.
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: 50.4896, 8.3806