The walls seem to be constructed to protect the Geatish heartland around today's Linköping from attacks from the Baltic Sea. Archaeological excavations have shown that the walls were constructed ca 800. Defense constructions were also built along the 20-kilometer narrow inlet Slätbaken that stretches from the Baltic Sea to Götavirke, and even pass it during the Viking Age when the water level was 1.5 meters higher. The measures that Geats had taken to protect the route have no match in the Viking Age Sweden.