The clearest dream I've ever had

I have record this one before I forget. It's significant because it was extremely clear, possibly the clearest dream I've ever had.

I was with some of my cousins in the attic of my great-grandmother's house, and we found a secret trunk containing an extensive collection WWI artifacts (uniforms, letters, weapons, etc.) that belonged to my great-grandfather. It was a very important historical find and would ultimately be donated to a museum. That great-grandmother's house existed in reality and that great-grandfather - her IRL husband - was in fact a WWI veteran. Given the clarity of the dream, I would be certain my family has a cache of historical artifacts somewhere, except that IRL:

- We already know about the WWI artifacts that great-grandfather left behind (just a few things, not an extensive collection) and they were donated to a museum already.
- The great-grandmother passed away at least 15 years ago and her house was cleaned out. Anything in the attic would have been found back then.
- I've never been in the attic of that house, at all, ever. And the cousins who were helping me were from the other side of the family - they are not at all related to that great-grandmother.
- All the artifacts were completely illogical. For example, the belt buckles were made out of wood, the in-dream reasoning being that they didn't have metal back then. The letters were written in some non-European language on papyrus scrolls with quills. The weapons (in this dream he took his weapons home from the war with him!) functioned on alchemic principles.

But it was so ridiculously clear, unlike any dream I've ever had.