This 2 Franc commemorative stamp from Monaco was issued in 1961 to mark the 60th anniversary of the discovery of anaphylaxis (1901–1961). The design honors Prince Albert I of Monaco, along with Charles Richet and Paul Portier, the French physiologists who made the discovery during marine research aboard Prince Albert’s yacht Hirondelle. The left side features the Physalia (Portuguese Man o’ War), the jellyfish that played a key role in their experiments. This issue beautifully combines Monaco’s royal maritime tradition with a landmark achievement in medical science.