There are numerous prehistorical and early historical ringworks and fortification ramparts in Central Europe that have erroneously, usually colloquially, been given the name Schwedenschanze, which means "Swedish redoubt", a schanze being a hastily erected, military fieldwork.
This name arose in connexion with the fighting during the Thirty Years' War, when the population of the Holy Roman Empire often used old field fortifications as refuge castles or hidden livestock pens. Particularly in Catholic areas this action was taken to protect people from the Protestant forces of the Swedish king, Gustavus II Adolphus. Whether the individual fortifications were actually used as fighting positions, however, is usually speculative. Many of the often well preserved earthworks in the forests of Europe were probably later associated wrongly with this religious war.
The history of these heritage sites often goes back several thousand years. They were frequently extended during the Early Middle Ages, for example, to defend East Francia and other regions in the 10th century from the Hungarian invasions.
It is true that in the 17th century, during the Thirty Years' War, numerous earthworks and schanzen were thrown up during the conflict. But these are clearly distinguishable from the older sites by their regular, geometric shapes. Occasionally there were also fortifications that were actually built by the Imperial Army, i.e. Catholic League troops that were later called Schwedenschanzen; such as the Schwedenschanze in the Rhön.
From west to east:
