Philippe la Renotiere von Ferrari had willed his stamp collection to a Berlin museum, but the French government seized it during World War I.
Notes on verification
Confirmed by multiple independent sources including Smithsonian National Postal Museum, Wikipedia, and specialized philatelic history sites. Minor variation exists in details of the seizure mechanism and timing, but core facts are consistent. [cascade flags: wikipedia_dropped_other_sources_exist | tier=silver indep_score=0.812 clusters=4 claim_tier=notable]
Sources
- Philately - Notable Stamps, Collections | Britannica (seed:culture_and_philosophy)
- https://www.si.edu/newsdesk/releases/world-s-rarest-stamp-now-display-national-postal-museum (corroboration)
- https://www.museumofphilately.com/subsites/j-hackmey-collections/collector/6 (corroboration)
- https://www.sandafayre.com/blog/ever-owned-a-ferrary/ (corroboration)
- http://catalogue.klaseboer.com/vol1/html/ferrari.htm (corroboration)