Auerbach - This is one of several fortresses along the Bergstrasse in southern Hesse, Germany. The castle was originally built by King Charlemagne (Emperor of the Holy Roman Empire) and rebuilt by Count Diether IV of the Katzenelnbogen dynasty in the second quarter of the 13th century. Today it remains standing atop a hill known as Urberg (part of the Melibokus) above the town of Bensheim-Auerbach.