David F.
Google
This was included in my ticket to the archbishop's palace, cathedral, and treasury. I am glad it was because it magnified the already great return on investment.
The artifacts begin with the Vikings, with displays of axes, swords, spearheads, etc. Continuing on, it goes through the Middle Ages with an immense display of swords, suits of armor, handcannons, and other weaponry. All of this took place on the first floor of the museum. Just this floor made the time worth it, but it only got better.
The next floor was all about WW1 and WW2. The number of guns, uniforms, propaganda posters, mortars, and machine guns was incredible. It was fantastically done, and you were able to learn an enormous amount about Norway's involvement in WW2. There was a lot of readable information that was interesting and informative. But, there were some (a lot) really bad typos in the English. You could still read it, but a lot of them were pretty funny.
I'd 100% recommend a visit here, whether you both the combined ticket or not.