More than 2,000 years ago the Celtic people believed summer came to an end on October 31st, so in anticipation of the end of "the season of life" & the beginning of "the season of death," Celts would celebrate Samhain or Samain (pronounced "sah-win") or "Summer's End." In the 19C, one academic explained, "The Samhain feast...was, like the Greek Apaturia, partly devoted to business...other wise the feast, which occupied, not only Samain or the first of November, but also the three days before and the three days after it." The festival segment of Samhain focused on the harvest & death of crops & the approaching season of cold & darkness, to symbolize the the transition from life to death. The Celts thought the veil between this world & the next was thinnest during Samhain & that spirits & fairies could more easily move between the two realms. Some might pass from the living to the dead, and some dead ancestors might come to visit during this time. The Celtic celebration of Samhain was the New Year’s Day on the Celtic calendar.
In ancient times the festival was said to be celebrated with a great assembly at the royal court in Tara, the archaic hill fort and bastion of the Irish kings. The festival began after a ritual fire was set ablaze on the Hill of Tlachtga. This bonfire served as a beacon, signaling to people gathered atop hills all across Ireland to light their ritual bonfires. This ritual was called the Féile na Marbh in old Irish, meaning the 'festival of the dead' took place on the night of Samhain, or “Oíche Shamhna” and and was said to fall on the 31st of October. The word 'bonfire' itself is a direct translation of the Gaelic tine cnámh or Bone Fire, because villagers were said to have cast the bones of the slaughtered livestock upon the flames. October was the traditional time for slaughter - for preparing stores of meat and grain to last through the coming winter. With the bonfire ablaze, the villagers extinguished all other fires and then each family then solemnly lit its hearth from the local common flame, thus bonding the families of the village together with the symbolic bones of their ancestors. English travelers of the 19C are said to have witnessed this ritual.
In some homes, a door would be opened to the west & a beloved dead relative would be specifically invited to attend the celebration. Villagers might leave a candle or other light burning in a western window to guide the dead home. On Samhain Eve, the Celts lit their bonfires & laid out harvest gifts for the souls traveling through the corporeal plane on their way to the next realm. Families would leave food & wine on their doorstep to aid the souls passing over & to keep the pesky ghosts at bay. Many wore costumes when leaving the house hoping to be mistaken for ghosts themselves. The Celts believed dressing up both honored the good spirits & helped avoid the bad ones.
Ancient Celtic legends supported this concept of transition from life to death. In one, Nero, while begging from door-to-door on Samhain, discovered a cave leading directly into the fairy realm. In another, gods called Fomorians demanded tribute from Celtic mortals, who offered harvest fruits to these gods at Samhain. This story reinforced the Celtic tradition of setting out harvest gifts for souls crossing over & for the ghosts gathered near at Summer's End. Sometime in the 8C, Pope Gregory IV changed the date originally set for All Saints' Day to the same day as Samhain, essentially merging the traditions connected to those holidays & making the church more attractive to non-believers. The Catholic Church established November 1st as All Saints Day (also known as All Hallows) & November 2 as All Souls Day.
A traditional Irish Halloween carved turnip jack-o-lantern
James Elder Christie (British artist, 1847-1914) Halloween Frolics
The traditions of "guising," & "mumming" grew into an event where masked individuals would go door-to-door disguised as spirits dancing & singing in exchange for food & wine. A 19C Scottish song noted, "In a guizing excursion, he sung some verses." The custom of mumming was first written about in the 1400s in English. In 1546, it was noted, "The disguising and muming that is vsed in Christemas tyme." By 1801, one sports writer explained, "A sport common among the ancients...consisted in mummings and disguisements." (The Danish word mumme meant to parade in masks. The term guising was first used in written English in 1563.) In order to see as they paraded at night, Irish participants would carve faces into turnips & potatoes to light as lanterns, as they passed from house to house, & to set outside their doorways to light dark steps & to scare away evil spirits.