Situated high above the historic town centre of Blankenheim, the impressive castle dominates the image of the castle town. Gerhard III probably built the castle at the beginning of the 13th century. Count Gerhard VIII had the castle demolished in the 15th century and rebuilt as a palace. When it passed from Blankenheim rule to the Counts of Manderscheid in 1468 by inheritance, Count Dietrich III of Manderscheid-Blankenheim had a pipeline built to the castle in order to improve the water supply that had previously been provided by a cistern. The approximately 1.5 kilometre long pipeline, which was partly built as a gradient pipeline and partly as a pressure pipeline and ran through a tunnel in parts, led from the spring through the valley "In der Rhenn" to the castle courtyard. It had to overcome a 12 metre deep valley and a 15 metre high mountain spur with the help of an aqueduct tunnel. The castle was redesigned several times: the medieval knight's castle was transformed into a baroque palace. The building had lost its importance as a fortress. The people of Manderscheid also wanted to impress their guests with representative facilities. Around 1730 they built a baroque garden with an orangery in front of the moat. In Blankenheim, the most important elements of the water supply of the late medieval castle are still preserved or recognizable: the spring catchment "In der Rhenn", parts of the pressure pipe through the valley, the inlet ditch in front of the tunnel, the Tiergarten tunnel and the water house on the south side of the Tiergarten. The tunnel is the only known example of its kind from the late Middle Ages.
Source:
blankenheim.de/de/freizeit/kultur/roemer-archaeologie/roemervilla/burg-blankenheim