The following article is from the Jeremiah Project:
History traces Halloween back to the ancient religion of the Celtics in Ireland. The Celtic people were very conscious of the spiritual world and had their own ideas of how they could gain access to it – such as by helping their over 300 gods to defeat their enemies in battle, or by imitating the gods in showing cleverness and cunning.
Their two main feasts were Beltane at the beginning of summer (May 1), and Samhain (pronounced Sah-ween) at the end of summer (Nov. 1). They believed Samhain was a time when the division between the two worlds became very thin, when hostile supernatural forces were active and ghosts and spirits were free to wander as they wished.
“During this interval the normal order of the universe is suspended, the barriers between the natural and the supernatural are temporarily removed, the sidh lies open and all divine beings and the spirits of the dead move freely among men and interfere sometimes violently, in their affairs”
(Celtic Mythology, p. 127).
The Celtic priests who carried out the rituals in the open air were called Druids, members of pagan orders in Britain, Ireland and Gaul, who generally performed their rituals by offering sacrifices, usually of crops and animals, but sometimes of humans, in order to placate the gods; ensuring that the sun would return after the winter; and frightening away evil spirits.
To the Celtics, the bonfire represented the sun and was used to aid the Druid in his fight with dark powers. The term bonfire comes from the words “bone fire,” literally meaning the bones of sacrificed animals, sometimes human, were piled in a field with timber and set ablaze. All fires except those of the Druids were extinguished on Samhain and householders were levied a fee to relight their holy fire which burned at their altars. During the Festival of Samhain, fires would be lit which would burn all through the winter and sacrifices would be offered to the gods on the fires. This practice of burning humans was stopped around 1600, and an effigy was sometimes burned instead.
By A.D. 43, Romans had conquered the majority of Celtic territory. During their rule of the Celtic lands, Roman festivals were combined with the traditional Celtic celebration of Samhain. The Romans observed the holiday of Feralia, intended to give rest and peace to the departed. Participants made sacrifices in honor of the dead, offered up prayers for them, and made oblations to them. Another festival was a day to honor Pomona, the Roman goddess of fruit and trees. The symbol of Pomona is the apple and the incorporation of this celebration into Samhain probably explains the tradition of “bobbing” for apples that is practiced today on Halloween.
As the influence of Christianity spread into Celtic lands, in the 7th century, Pope Boniface IV introduced All Saints’ Day, a time to honor saints and martyrs, to replace the pagan festival of the dead. It was observed on May 13. In 834, Gregory III moved All Saint’s Day from May 13 to Nov. 1 and for Christians, this became an opportunity for remembering before God all the saints who had died and all the dead in the Christian community. Oct. 31 thus became All Hallows’ Eve (‘hallow’ means ‘saint’).
Sadly, though, many of the customs survived and were blended in with Christianity. Numerous folk customs connected with the pagan observances for the dead have survived to the present.
In 1517, a monk named Martin Luther honored the faithful saints of the past by choosing All Saints Day (November 1) as the day to publicly charge the Church heirarchy with abandoning biblical faith. This became known as “Reformation Day,” a fitting celebration of the restoration the same biblical faith held by the saints throughout church history.