The remains of the Castle can be visited
Poppberg Castle
On the rocky summit of the Poppberg in the Franconian Jura lies the Poppberg Castle Ruin, a former noble castle from the High to Late Middle Ages. It is located near the village of Poppberg in the municipality of Birgland in the Amberg-Sulzbach district, Bavaria.
History+
Poppberg Castle, a hilltop castle, was likely built in the 13th century by the Counts of Sulzbach. Between 1353 and 1373, it was owned by Emperor Charles IV. After passing to Margrave Otto of Brandenburg, the castle came into the possession of the Bavarian Dukes Johann and Stephan in 1379, who sold it to Count Palatine Ruprecht III in 1395.
Source: Wikipedia · Licence: CC BY-SA 4.0 · Image: http://de.wikipedia.org/wiki/Datei:Burgruine-Poppberg03.JPG
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: 49.4134, 11.5839