Another ancient symbol that derives from the Celtic pagan holiday of Samhain is the wearing of masks and costumes. On the eve of Samhain (October 31st) it was believed that the dead returned to the realm of the living and in order for the Celts to protect themselves against these spirits and the mischief that they caused it was a common practice to wear masks and costumes in order to disguise the identities of the living.
Halloween costumes have come a long way from the traditional costumes and masks worn during Samhain. The ancient costumes were created from the skins and heads of animals scarified to the Celtic deities during this period.
During Samhain the Celts believed that the dead literally walked among the living and due to fear of their malevolent agenda costumes and masks were worn for the protection. The belief was that by disguising themselves the sprits from the underworld would assume that they too were a spirit or if one of these particular spirits bore a grudge against the living their identities would be protected. It is a tradition that, although significantly altered, has lasted the test of time and it is the basis for why millions of people across the world wear costumes on Halloween today.