Steinbruch

More information about the history

Image: Section through the Drachenfels’ volcanic plug and the trachybasalt vent of the Wolkenburg

The Drachenfels is what remains of a volcano from more than 25 million years ago (from the tertiary period). The hill is formed from trachyte, a light-coloured volcanic rock. It is thought that the trachyte magma was not emitted as lava but became stuck in the soft trachyte tuff under the surface of the earth and distended like a balloon. In the case of the Wolkenburg, located to the east of the Drachenfels, the various stone quarrying phases meant that the hilltop disappeared and the hill lost height – estimates vary between 10 and 30 m.

Image: Roman wedge marks / depiction of Roman workers quarrying stone (diorama, Siebengebirgsmuseum)

Trachyte, which is easy and precise to work with, was first quarried by the Romans. They used it to build the camps for their legions in Bonn and Cologne, as well as Colonia Ulpia Traiana, a Roman town near to the present day town of Xanten. In the Middle Ages, the popular trachyte stone was used for the construction of a number of churches in the Rhine region, e.g. for Cologne Cathedral and Bonn Minster. The characteristic wedge marks from blasting the blocks of stone can still be seen today near to Drachenburg castle and on the western slope of the Drachenfels. Unique for the entire quarrying area are the mysterious carvings on a vertical rock face near the Drachenfels. They depict a phallus as a fertility symbol next to a rooster.

Image: Drachenfels with stone chute (copperplate engraving), Matthäus Merian, 17th century

The long tradition of quarrying has left behind large cavities bordered by rock. On the western slope of the hill, shallow V-shaped furrows, sometimes with narrow channels in the rock, can still be seen today. This is what remains of chutes which were used to transport pieces of the blocks and take them to the banks of the Rhine, where they were loaded onto ships.

Image: Depiction of Roman workers transporting stone using wooden rollers (diorama, Siebengebirgsmuseum)Image: Construction work on Cologne Cathedral, 1855 (salt print), Johannes Franciscus Michiels

According to legend, trade with Drachenfels trachyte was very profitable, thanks to the construction of Cologne Cathedral. “As a number of knights from throughout the land gathered together, they showed each other their rings and each of them boasted about the precious gems which adorned them. Burgrave Johann von Drachenfels also showed off his ring in which was mounted a small piece of the rock cut from his hill. He declared that the value of his stone was a match for that of the other gentlemen’s gems. Everyone laughed at him but he continued, ‘It doesn’t glisten like yours, but it earns me many hundreds of gilders every year from the patrons of Cologne Cathedral who need the stone to build the church; but what use are your stones for you!’”

Image: Cologne Cathedral, around 1900

For the completion of Cologne Cathedral, the cathedral workshop had to find other sources for the second phase of the construction (1842–1880) due to the closure of the Drachenfels quarries.

Practical information

At the Siebengebirgsmuseum, numerous exhibits on quarrying on the Drachenfels are on permanent display
Siebengebirgsmuseum Königswinter, Kellerstraße 16
Tue–Fri 2 PM–5 PM, Sat 2 PM–6 PM, Sun 11 AM–6 PM, Mondays closed > Website