First Week Of 2016 Excavations At Skällvik Castle
The famous royal castle of Stegeborg sits on its island like a cork in the bottleneck of the Slätbaken inlet (see map here). This waterway leads straight to Söderköping, a major Medieval town, and to the mouth of River Storån which would allow an invader to penetrate far into Östergötland Province's plains belt. The area's first big piece of public construction was 9th century fortifications intended to guard this entrypoint, in the shape of the Götavirke earthen rampart some ways inland and a wooden barrage at Stegeborg.
Source: scienceblogs.com