I dont even know where the Germans come in to this.
Hedeby was the second largest Nordic town during the Viking Age, after Uppåkra in present-day southern Sweden
Hedeby was the second largest Nordic town during the Viking Age, after Uppåkra in present-day southern Sweden,2
And the only thing i can find regarding the Slavs, is that in 1066 they sacked and burned down Hedeby.
In 1066 the town was sacked and burned by West Slavs.
This happened 16 years after the King of Norway had sacked and set the town on fire.
King of Norway
King of Norway 1050ad
The town was sacked in 1050 by King Harald Hardrada of Norway during a conflict with King Sweyn II of Denmark. He set the town on fire by sending several burning ships into the harbour
I can also find no evidence that the Danish reconquered Schleswig from the Germans.
Schleswig is an old norse word, which means "bay of the Schlei".
bay of the Schlei
old norse word
in Old Norse and Danish. Schleswig or Slesvig therefore means "bay of the Schlei".
And even when Germans did begin to live in Schleswig in 1544, they were only vassals of the Danish kings
In 1544, Gottorf Castle became the residence of the local rulers. The dukes of Gottorf were vassals of the Danish kings and ruled over much of present-day Schleswig-Holstein
I can also find no evidence that the Danes reconquered the town.
They founded the town.
. Following the destruction, Hedeby was slowly abandoned. People moved across the Schlei inlet, which separates the two peninsulas of Angeln and Schwansen, and founded the town of Schleswig.
I can also find nothing regarding 983ad
Regarding the sack of Hamburg. Yes. The Danes did sack Hamburg.
But this was nothing to do with Germans.
It was to do with Charlemagne, who was the Holy Roman emperor.
And Charlemagne was the man that ordered the construction of Hamburg.
The name Hamburg comes from the first permanent building on the site, a castle which the Emperor Charlemagne ordered constructed in AD 808.
However in 845ad, 138 years before your 983 approximation, Hamburg was destroyed by the Vikings.
Hamburg was destroyed and occupied several times. In 845, 600 Viking ships sailed up the River Elbe and destroyed Hamburg, at that time a town of around 500 inhabitants.[24
This was nothing to do with Germans however. It was to do with the fact that the Holy Roman empire was stepping on Danish territory.
The holy Roman empire was not German.