Masks have been worn in nearly all cultures, for various reasons, since the Stone Age. Masks have been worn as a form of disguise, by an actor in a performance, as part of a religious ceremony, as part of membership in a secret society, as punishment for a criminal or in celebration of a holiday.
Egyptians used masks as part of their burial ceremony. The masks that were placed upon the face of the deceased often contained spells intended to protect the spirit on its journey into the afterlife. The masks were usually painted with gold and contained precious stones.
Many of Africa's native cultures used masks as part of their religious ceremonies, as well as part of ceremonial costumes. They often were made to represent the spirits of ancestors or of certain local deities. A dancer wearing the mask was sometimes thought to be possessed by the spirit represented by the mask he wore.
In Japan, China and other parts of Asia, masks had religious purposes or were part of traditional theater. Many of the masks were influenced by Buddhist, Hindu and Indian literature, and were inspirations in various Asian art forms including theater.
Native American masks were used for purposes similar to that of the masks in Africa. However, in addition to its spiritual function, the Native American mask was sometimes used for entertainment or for medicinal purposes.
The comedy and tragedy masks have come to represent theater. These masks were first developed in ancient Greece and had both an entertainment and religious function. A similar tradition is that of the masked fool; a masked fool of some sort is found throughout many cultures and continents. The masked fool's purpose in theater was to keep order. The fool kept children from being unruly and distracted the audience from the dressing room or scene changes. In society, the fool questioned the status quo without the repercussions others might have faced.
In medieval time, a punishment often meted out was that of forcing the criminal to wear a shame mask or brank. The metal masks were worn in public displays and might have included the "swine mask" for a man who had mistreated a woman or the "hood of shame" for a student who had performed poorly. Branks might have been worn by a woman for nagging her husband or gossiping. The brank often included a tongue-depressor with sharp edges that was placed in the mouth to make talking painful.
The tradition of Halloween masks and Halloween costumes finds its origins in Celtic culture. Disguises were used to confuse the ghosts that came out on Samhain, a festival at the end of the harvest season. Frightening masks were often used because these were believed to scare away malicious spirits.