Kven Sea
Kven sea ("Cwen sea") is mentioned as the northern border for the ancient Germania in "The Old English Orosius", the history of the world published in England in 890 CE with a commission from King Alfred the Great himself. The word "kven" most likely comes after the Kven people, implied that they have used the area fairly extensive. The name Kven sea was probably the same as the Gulf of Finland, although the Gulf of Bothnia has also been suggested. But, in a norwegian source from 1922 "Kvænhavet" (Kven sea) is mentioned as another name (nickname) for the  White Sea. Included in "Orosius", there is a short mention of the Kven Sea by a Norwegian Viking Ottar, but the Kven Sea is unknown outside "Orosius". Borders of the ancient Germania were described in "Orosius" as follows: Kven Sea in other sources. The total absence of the name "Kven Sea" from all Norwegian and Swedish sources is noteworthy, though, and sagas that describe the era during which Ottar lived use the name "Helsingjabotn" for the Gulf of Bothnia, for example in the Orkneyinga saga. If Kven Sea was a name used for the Gulf of Bothnia, it along with  all of its possible variations seem to be completely missing from the Scandinavian namespace in later times. Finnish historian Kyösti Julku has, however, suggested that "Kajano More", which appears in Russian documents from the 14th to 16th centuries in different spellings as the name for the Gulf of Bothnia, might have been an equivalent of Kven Sea. But that theory does not explain its total absence in Scandinavian sources.