Theory of displacement dictates when people covered up their naughty bits they outwardly demonstrated vestiges of their private parts (and hence gender), on their head and on their feet. This is the primary reason we have male and female hats, hair styles, and shoes. A similar genderisation can be seen in tribal masks. Dome head for male; and invaginated head for female
Hats and shoes, were worn for decoration long before they were put to a practical use, such as protection from the elements or stray arrows. Throughout antiquity, hats were a symbol of status and rank. Like early shoes, animal skins may have been used to adorn the head but only after tanning was discovered. Felted hats have a long linage in hat making.
In more recent history, hats became a popular form of costume for men in the late 14th and 15th centuries. This may have been in part related to returning Crusaders bringing with them the costume of Middle East to European courts. Whilst women were expected to cover their hair with veils etc., costume hats began to appear from the 16th century onwards and were scaled down courtier hats. More sumptuous materials were used with silk, velvet, taffeta, leather, felt and beaver all favoured by the 15th century, Dandies.
Hat wearing for men was almost obligatory whereas only women from the upper and middle classes wore hats. During this period, there was little difference in the hats worn by men and those worn by women. This was quite risqué for the time since cross dressing was viewed very suspiciously.
Hats continued to represent status throughout the 18th, 19th century and even the 20th century. Italian Milliners from Milan supplier of fancy goods, such as straw hats, gloves and other accessories but later in the 1770s, milliners started to design and make hats. The high wigs worn by the 18th century aristocracy was later mirrored in the top hats of the bourgeoisie (Lord Snooty) and 19th century moguls of industry. Fashionable hats for women only became vogue in the 18th Century.
At the same time the felt trilby, came to symbolize democracy and revolution and were generally associated with bohemians, intellectuals, artists and country life. Sumptuary law in the US meant every male had to wear a hat. This not only was a boost to the US millinery industry but also added to the lexicon of style and status.
The World Wars established in the public conscience the protective function of headgear and subsequent health and safety legislation have ensured a complete new lease of life for the humble hat. Otherwise costume hats remained fashionable until the 1960s when they underwent a steady decline.
The origin of graduation hoods is clouded and may be Celtic.
Mortarboard (square or trencher) consists of a horizontal square board fixed upon a skull-cap, with a tassel, or liripipe. The mortarboard is thought to have evolved from the biretta and was worn by Christian Clergy from the 10th century onwards. There is a certain division of opinion between experts and some believe the biretta derived from the Roman pileus quadratus, a type of skullcap. Others think the origins may be Islamic brought back to Europe by the Crusaders.