The Altenburg (Deinsberg Castle Ruins): It was probably built in the second half of the 12th century. At that time, Emperor Barbarossa had several castles built to secure his country's borders. At that time, Theisbergstegen consisted of two towns belonging to different territories. It is likely that the Altenburg was called Deinsberg Castle, as it was customary for lords and knights to name themselves after their castle residence. There is ample evidence of this, for example, Knight Anselm and Servant Heinrich, both of Deinsberg. The castle was approximately 60 meters long and 33 meters wide. The residential tower and gate tower were elevated and separated by a moat, which probably contained a cistern for rainwater. It was probably destroyed as early as 1400.