The International Philatelic Federation was formed in 1926.
Notes on verification
Confirmed by official FIP website, Wikipedia, Rice University library guide, and other independent sources all citing 18 June 1926 as the founding date in Paris. [cascade flags: wikipedia_dropped_other_sources_exist | tier=silver indep_score=0.875 clusters=2 claim_tier=everyday]
Sources
- Philately - Notable Stamps, Collections | Britannica (seed:culture_and_philosophy)
- https://www.f-i-p.ch/fip-organisation/about/ (corroboration)
- https://libguides.rice.edu/c.php?g=1284052&p=9425949 (corroboration)