The Kyffhäuser (German pronunciation: [ˈkɪfˌhɔɪ̯zɐ],[1] sometimes also referred to as Kyffhäusergebirge) is a hill range in Central Germany, shared by Thuringia and Saxony-Anhalt, southeast of the Harz mountains.

The settlement of Tilleda, located below the northern rim of the range, was already mentioned as Dullide in the early 9th century in the Breviarium Sancti Lulli register of Hersfeld Abbey.

In 1698 Count Albert Anton of Schwarzburg-Rudolstadt had a Baroque hunting lodge erected at the hamlet of Rathsfeld in the centre of the Kyffhäuser range.

Last used as a residence by Prince Günther Victor of Schwarzburg after his abdication in 1918, it was turned into a recreation home of the Kyffhäuserbund veterans' association in 1925.

According to a king asleep in mountain legend, Emperor Frederick Barbarossa, who actually drowned on 10 June 1190 in the Calycadnus River near Seleukeia in Asia Minor during the Third Crusade, is not in fact dead, but sleeps in a hidden chamber underneath the Kyffhäuser hills.

As in the similar legend of King Arthur, Barbarossa supposedly awaits Germany's hour of greatest need, when he will emerge once again from under the hill.

The Barbarossa myth was first documented in the late 17th century and later popularized by the Brothers Grimm and a poem written in 1817 by Friedrich Rückert.