Jomsborg
Jomsborg was a legendary
viking settlement in
Pomerania, which is located by the
Baltic Sea. It's generally disputed whether such settlement existed at all, all of the proofs are coming from later era and from distant Islandia. Contemporary sources mention rather city known as Julin, Jumne or
Wolin, which supposedly was city known from
Slavic pirates, where also
Danes and other Scandinavians could easily found refugee,
Harold Bluetooth had to take refuge from his son here in the late 900s.
See also: Early Swedish Kingdoms, Scandinavian connections to Mieszko I