The second fireplace is in the northeast corner of the seventh floor, which is the largest and brightest room in the tower with narrow walls and three arched openings. The double arcade windows also present here served to date this tower area from an art historical point of view to the first quarter of the 13th century. Both fireplaces are connected by a 20 meter high chimney, which is only partially integrated into the wall and otherwise runs in a projecting wall. Missing traces of soot show that the fireplace has not been used for 445 years. Some formwork boards found in the chimney can be used to explain the high medieval construction technique of the chimney without scaffolding and cranes.[1]
As the existing windows, the fireplaces and the chimney mantle inside the tower suggest, the tower was once habitable and could be accessed via the entrances at a height of 9 meters. It could have been used as a place of refuge during the Carolingian period, but also as a treasury, mint or archive. The tower originally had a crenellated crown instead of today's pyramid roof. Large stonemason's marks can be seen on the middle wall zone, including several mill playing fields on the south side. In the area of the quarry stone masonry, the tower is still 1.6 m thick and decreases by 10 cm with each floor.[2]
During the Second World War, a two-meter-thick reinforced concrete false ceiling was installed inside the tower in order to be able to store the glass windows of the Regensburg Cathedral in the tower to protect them from bombs.
Whether the Roman tower has a connection to the campanile of the collegiate church to the old chapel, 200 meters further south, is being investigated.
Source: Wikipedia