Opera hat described as: Some sources have taken this to describe an early folding top hat, although it is not explicitly stated whether Dollman's design was specifically for male or female headgear. Dollman's patent expired in 1825. Operating from Poissy, Paris, France, around 1840, Antoine Gibus's design for a spring-loaded collapsible top-hat proved so popular that hats made to it became known as "gibus". They were also often called "opera hats" due to the common practice of storing them in their flattened state under one's seat at the opera, though the term can also refer to any tall formal men's hat. The
Top hat men's hat. The characteristic snapping sound heard upon opening a gibus suggested a third name, the "chapeau claque", "claque" being the French word for "slap". Until World War I the top hat was maintained as a standard item of formal outdoor wear by upper-class males for both daytime and evening usage. Considerations of convenience and expense meant however that it was increasingly superseded by soft hats for ordinary wear. By the end of World War II, it had become a comparative rarity, though it continued to be worn regularly in certain roles. In Britain these included holders of various positions