Jomsborg was a legendary Viking settlement in Pomerania by the Baltic Sea. It is generally disputed whether such a settlement existed at all, all proof coming from later times and from distant Iceland. Contemporary sources mention a city known as Julin, Jumne or Wolin, which supposedly was a home of Slavic pirates, but where Danes and other Scandinavians could also easily find refuge. The name Viking is a loanword from the native Scandinavian term for the Norse warriors who raided the coasts of Scandinavia, the British Isles, and other parts of Europe from the late 8th century to the 11th century. ... Historic Western Pomerania (outlined in yellow) on the background of modern country borders. ... The Baltic Sea is located in Northern Europe, from 53 deg. ... Wolin is the name shared by an island located in the Baltic Sea located just off the Polish coast, and a town located on the island. ... The Slavic peoples are defined by their linguistic attainment of the Slavic languages. ...
It was conquered by the disinherited Swedish prince Styrbjörn Starke who later gave it to the Danish king Harold Bluetooth. Styrbjörn the Strong (Styrbjörn Sterki) or Styrbjörn the Swedish Champion (Styrbjörn svÃa kappi) was according to the Norse sagas the son of Olof (II) Björnsson, and the nephew of Eric the Victorious. ... Harold Bluetooth Gormson (Danish Harald Blåtand, Norwegian Harald Blåtann) (ca 935- November 1, 986), sometimes Harold II, succeeded his father Gorm the Old as king of Denmark in 958 (or 959) and was king of Norway for a few years, probably around 970. ...
Harold Bluetooth had to take refuge from his son here in the late 900s. Harold Bluetooth Gormson (Danish Harald Blåtand, Norwegian Harald Blåtann) (ca 935- November 1, 986), sometimes Harold II, succeeded his father Gorm the Old as king of Denmark in 958 (or 959) and was king of Norway for a few years, probably around 970. ... Centuries: 9th century - 10th century - 11th century Decades: 850s - 860s - 870s - 880s - 890s - 900s - 910s - 920s - 930s - 940s - 950s Years: 900 901 902 903 904 905 906 907 908 909 910 Events: Categories: 900s ...
Jomsborg was founded in 1975; it's true that it was a CUSFS offshoot and I understand it's true that the people responsible weren't very happy with the CUSFS of the day.
Exactly what their particular interests were I don't know, but Jomsborg is fantasy society, not a reborn SF society, which might be considered a clue.
CUSFS and Jomsborg officially amalgamated in the mid-to-late 1990s (I don't recall the exact date, though 1997 doesn't seem implausible); it was presented, not unfairly, as healing a divide.