There were four Jewish congregations in Oslo in the early 1900s; by 1917, there were only two serving some 1,300 Jews, according to this article.
In 1920 and 1921 they had constructed their own buildings. synagogues. The first, in 1920,was Det Mosaiske Trossamfund i Oslo. It reopened after Jewish survivors returned to Norway in 1945 and after. Still open for services, it is located at 13 Bergstien.
The other, at 15 Calmeyers St., remained closed after the Holocaust as there were too few Jews in Oslo to maintain two congregations.
Calmeyers was used for various businesses; today, parts of the building is now occupied by the Oslo Jewish Museum and it will be used as a museum and cultural center.
A temporary exhibit in honor of Norwegian poet Henrik Wergeland will open this month., and the museum will offer a week of Jewish culture, with theatre, concerts and other events.
The museum was officially opened by Crown Prince Haakon.
Norway was one of the last European countries without such a museum in its capital. Although Trondheim has had a local Jewish museum, Oslo had little display of Jewish history and culture other than minor exhibits at the Norwegian Folk Museum and at the recently opened Holocaust Center.
The old Calmeyers Gate 15B's synagogue has been restored and reopened to tell the story of Jews in Norway since the first immigrated more than 150 years ago.
Norway's government ministers for defense and culture joined the crown prince at the opening, along with Israel's ambassador to Norway.
The debut exhibit describes how Norwegian Jews influenced cultural life and the struggle against German occupation during World War II.