Castle Frankenberg erected in the reign of Charlemagne, it is because all the legends of the castle link the structure with the name of this course the great ruler. So, the most famous legend says that at the time of the wedding ceremony with Karl Frustradas among the guests serpent appeared with a small ring in his mouth. This ring, she threw a Cup filled with wine, and the Cup was in this moment in the hands of the Emperor, who took the incident as a good omen and put the ring on the finger of the couple. After that he began to love his wife as obsessed. Even after the death of Fastrada, it was difficult to leave her lifeless body. He refused to bury her, day and night spent inconsolably over her body, but this time his power downfall. When he finally fell asleep, the court threw the ring in the forest pond, after which the Emperor is alive again. But from the moment he was forced to return to the castle in order to find peace there.

After his death, quite a long period of time, the castle passed to different owners, were destroyed, even partially was once flooded. In the period of 1941-1945 in the castle there was a special laboratory of the famous Professor Hugo Junkers. He is the Creator of military aircraft of Germany.

After a half dozen years after the war, the castle was completely restored, however, occasionally it is closed for renovation, to preserve for future generations. In one of the rooms opened a Museum dedicated to the history of the German town of Aachen. Now the castle belongs to a number of cultural centers, where various activities of a public nature.