Epstein
Epstein is located in the Hoch Taunus, being the name of a town and castle.  The castle was founded in the 900s, making one of the oldest of its type in the region.  It received official mention in 1122.  Supposedly the castle was named after a Knight Eppo who saved a beautiful woman from an evil giant.  The Lords of Epstein used the castle as a residence and seat of government, and over the years it was expanded and improved.  But in 1492, the Lords of Epstein, in desperate straits, pawned off half of their castle to the Landgrave of Hesse.  By the 1500s, the Epsteins lost the castle completely to the Elector of Mainz.  By the 1800s, the castle fell into disuse and decay.
Entrance into the castle is through the western gate, and though in ruins a good part of the structure is extant. 

The photo at left shows that the primary residential hall was at least three stories.




The photo below shows the entrances to the keep.  It appears that the castle had at least three separate entrances to the keep as the tower was fully integrated with the rest of the structure.  This had both positive and negative aspects, the former meaning that communication within the entire castle was more effective and the latter being that more entrances meant more directions for attack.

These photos were taken in 2007.  The official website for the town of Epstein is here.
The photo at left is that of Konigstein, the two castles clearly visible to each other on a reasonably clear day.  This shot was taken from Epstein's keep.

Here is the direct link to my Konigstein page.
Left above and left, two views of the castle layout as seen from the keep.  The lower of the two shows the area that is today used for small concerts and theatrical performances.