Drachenfels (dräˈkhənfĕls) [key] [Ger., = dragon's rock], mountain, 1,053 ft (321 m) high, in the Siebengebirge, W Germany, on the Rhine. It is of volcanic origin. In legend, it is the scene of Siegfried's triumph over the dragon. The Drachenburg, a fortress that is now in ruins, was built on the mountain (probably in 1117) by Archbishop Frederick I of Cologne. It was captured by the Swedes (1632) and by the Spaniards (1633) in the Thirty Years War.