> They basically had a fishing industry and that's it.
While it certainly wasn't a rich nation in the first half of the 1900s, Norway in 1938 was actually the world's 4th biggest shipping nation, and owned 7% of the world's tonnage[1]. The forest industry was also significant (pretty interesting historical overview at [2]).
> Norway before the discovery of North Sea oil was one of the poorest nations in Europe.
Not really. In 1969, the GDP per capita of Norway was $9,899. Compare that to Sweden ($12,540), UK ($10,552), Ireland ($6,089), Germany ($10,440), Finland ($8,878), Italy ($9,566), Portugal ($4,987) etc.
You're off by a few years. Norway in the first half of the 20th century was certainly one of the poorest in Europe. This held true through the (global) great depression, which was coupled with and compounded by their own home-grown economic crisis.
However, the Norwegian economy had made substantial progress in the post war years - prior to and independent of oil.
Half-Norwegian / Half-American here. Comparing the stories I was told from the grandparents and great-grandparents on each side, this checks out at least anecdotally. Norway in 1900--1940 sounded like absolute dirt poverty compared to the USA in 1900-1940.
Also my (Norwegian) mother born just after WWII grew up without electricity and farmed with hand tools
Norway was poor before they found oil. They basically had a fishing industry and that's it.
Britain was an empire that never saw the sun set.