Jomsborg

Jomsborg or Jómsborg (German: Jomsburg) was a semi-legendary Viking stronghold at the southern coast of the Baltic Sea (medieval Wendland, modern Pomerania), that existed between the 960s and 1043. Its inhabitants were known as Jomsvikings. Jomsborg's exact location, or its existence, has not yet been established, though it is often maintained that Jomsborg was somewhere on the islands of the Oder estuary.Lauritz Weibull dismissed it as a legend.

Jomsborg is often thought to be identical with the present-day town of Wolin (also Wollin) on the southeastern tip of the isle of Wolin, probably located at Silberberg hill north of the town. In the Early Middle Ages, modern Wolin was the site of a multi-ethnic emporium (then known as Jumne or Julin). The Nordic sagas use "Jómsborg" exclusively, while medieval German histories use "Jumne" or "Julin", with the alternate names, some of which may be spelling variants, "vimne", "uimne", "Jumneta", "Juminem", "Julinum", "uineta", "Vineta" and "Vinneta".

In 1931/32, Pomeranian historian Adolf Hofmeister (1883-1956) suggested, through comparison of the events reported by the different chronicles, that all these terms describe the same place, which is at or near the modern town of Wolin. However, this is by no means universally accepted; Professor and historian Steven Fanning writes: "The Trelleborg-type fortresses of Denmark have been taken to be actual examples of Jómsborg-style camps of such warriors and Wolin in Poland was believed to be the actual Jómsborg. However, all such attempts to locate Jómsborg or encampments of the Jómvikings have failed, leading many to doubt that Jómvikings ever existed outside of literature." According to Władysław Filipowiak there are several dated sources which attest to the presence of a company of armed Vikings at the end of the 10th century in Wolin, who may have been installed there as mercenaries by the Polish king Bolesław Chrobry.

...
Wikipedia