Philippe la Renotiere von Ferrari's stamp collection was sold at auction between 1921 and 1925 for $2 million.
Sources
- Philately - Notable Stamps, Collections | Britannica (britannica.com)
- https://www.paulfrasercollectibles.com/blogs/most-recent/the-greatest-stamp-collection-ever-the-ferrary-collection (paulfrasercollectibles.com)
- https://www.measuringworth.com/datasets/exchangeglobal/result.php?year_source=1920&year_result=1940&countryE%5B%5D=France (measuringworth.com)