“[A] series of myths arose in various European countries about the return of a former great king, who is just sleeping, waiting for his time to return and save his homeland. These “king in the mountain” myths have appeared across the world, but have been most prevalent in Europe, featuring both mythical and real historical figures, such as King Arthur, Charlemagne, and King Sebastian I of Portugal. Here, we will focus on two of the most prominent of these myths: the long slumber and future return of the great Holy Roman Emperor, Frederick Barbarossa, and the last Byzantine emperor, Constantine XI Palaiologos.”
See also the article “Bergentrücking” in: Enzyklopädie des Märchens.
Von Reinhard Kirchner – <span class=”int-own-work” lang=”de”>Eigenes Werk</span>, CC BY-SA 3.0, Link