The ancient Druids believed that on the eve of November 1st, the spirits of the dead returned to visit the world of the living, and that a lot of these spirits had harmful intent. The priests would wear masks to disguise themselves as spirits to conduct the rituals of Samhain in the hopes of tricking the real spirits, making them believe the Druids were spirits as well and not living humans. In these disguises, the priests believed they would become victims of the roaming evil spirits, or of fairies, or any other nonhuman, supernatural, entity. Disguises were also worn by the average people to confuse the wandering ghosts of ancestors who may want to take them back to the land of the dead; most often this involved wearing the clothes of the opposite gender. In the Middle Ages, and beyond, people wore masks and costumes to gather on Samhain and practice the Old Religion. They wore the costumes so that if seen, they couldn’t be turned in to the authorities and thus be charged with witchcraft.
In medieval Britain, a custom known as “souling” was a common practice. It let the poor beg for food, or soul cakes (oatcakes, or square pieces of bread containing currants), while dressed in disguises. The masked people would travel door to door offering prayers for the deceased in exchange for the soul cakes. The “guisers” accepted just about any food offered, and they also gladly accepted money. The prayers for the recently dead to leave limbo and enter into Heaven increased with the number of donations. As time passed, this custom became less and less serious, and became more a fun event. Children would roam house to house, souling, singing songs and begging for food. They would play tricks on those people who denied them a treat.