Danevirke

The Danevirke (modern Danish spelling: Dannevirke; in Old Norse Danavirki ; in German Danewerk ; is a system of Danish fortifications in Schleswig-Holstein. This important linear defensive earthwork was constructed across the neck of the Cimbrian peninsula during Denmark's Viking Age. It was last used for military purposes in 1864.

The Danevirke stretches from the marshes in the west of the peninsula to the town of Schleswig, which lies beside the Schlei (Danish: Slien) on the Baltic Sea coast, near the former Viking trade centre of Hedeby. Another wall, between the Schlei and the town of Eckernförde, defended the Schwansen peninsula.

According to written sources, work on the Danevirke was started by the Danish King Gudfred in 808. Fearing an invasion by the Franks, who had conquered heathen Frisia over the previous 100 years and Old Saxony in 772 to 804, Godfred began work on an enormous structure to defend his realm, separating the Jutland peninsula from the northern extent of the Frankish empire.

Carbon-14 dating however, dates the initial construction to be in the second half of the 7th century, and Chronological dating suggest that construction began not very long after 737 (a few decades before the reign of Gudfred).

Read more about Danevirke:  Archaeological Record, Size, Symbolism, Second War of Schleswig, Stages in The Building of The Danevirke, The Danevirke in World War II, The Danevirke in Popular Culture