With the destruction of the city of Simmern in May and September of 1689, the Römerberg bastion also fell. An engraving by Merian depicts the corner tower of the former city fortifications with a round tower cap and a window-like opening in the bottom of the tower. The old bastion was accessed via a fear hole (cupola with an opening) in the ceiling, which suggests it was used as a prison in the past. The diameter of the basement is 4.40 meters, the thickness of the outer wall is 1.80 meters and the depth to the rock is 8.75 meters. The upper part of the tower probably served as a guard room. Remnants of the entrance portal were found. As a result of the destruction, parts of the hood fell into the tower interior.
In March 2003 a piece of the bastion wall above Mühlengasse broke out. This was followed by restoration and an archaeological survey. The analysis showed that the cavity in the bastion had been filled with various materials (pottery, animals and rubble) since the 19th century in particular. The collapse of the wall was caused by accumulated water that could no longer drain off and increased the internal pressure. The renovation of the bastion took place between 2005 and 2006 as part of the urban renovation program in cooperation with the State Office for the Preservation of Monuments and the architects König.