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
Chapeau 1250, but was not used in arms till the year 1300. Until that time, the cardinals were represented with mitres. Archbishops and patriarchs bore a green hat, with four rows of tassels; bishops wore the same color, but with three; abbots and apostolical prothonotaries with two. The chapeau is also sometimes used as a mark of secular dignity, such as a cap, or coronet armed with ermine, worn by dukes, etc. The crest is borne on the chapeau; and by the chapeau the crest and coat are separated; it being a rule that no crest must touch the shield immediately.