Please note that the content of this book primarily consists of articles available from Wikipedia or other free sources online. The Kyffhäuserkreis is a district in the northern part of Thuringia, Germany. Neighboring districts are the districts Mansfeld-Südharz, Saalekreis und Burgenlandkreis in Saxony-Anhalt, and the districts Sömmerda, Unstrut-Hainich and Eichsfeld. In the 12th century there was a castle on the Kyffhäuser mountains, which was built during the reign of emperor Frederick I. According to the local legend, the emperor did not die, but instead went to sleep in this castle.