Halloween is older than the costumes, older than the sweets, and considerably older than the pumpkin. What we do on 31 October is a compound of at least three things: an Iron Age seasonal festival, a Christian feast for the dead, and a Victorian appetite for parlour games. Pulling them apart tells you why the night feels the way it does.
Samhain: the year turns
The oldest layer is Samhain (roughly "sow-in"), marking the end of the harvest and the start of the darker half of the year in Gaelic Ireland, Scotland and the Isle of Man. It was one of the four quarter days that structured the Celtic year, and the most freighted.
Samhain sat on a threshold, and thresholds were dangerous. The herds came down from summer pasture, the killing of livestock began, and the community settled in for winter with everything it had. Medieval Irish literature places a great deal of supernatural activity at Samhain — the sídh, the burial mounds, stand open, and things come out of them.
That is the origin of the idea people repeat every October: that the boundary between this world and the other thins. It is a genuinely old notion, and it explains the disguises. If the dead are abroad, you would rather not be recognised.
All Hallows: the Church takes the date
In the eighth century, Pope Gregory III fixed the feast of All Saints — All Hallows — on 1 November, with All Souls' Day following on 2 November. That made 31 October All Hallows' Eve, which contracts to Hallowe'en.
Whether the Church deliberately placed the feast over Samhain is argued about endlessly. The honest answer is that we do not know. What is clear is the result: a three-day season of the dead, running from the eve through All Saints to All Souls, in which the living prayed for the departed and the departed were understood to be close.
This is the layer that gave us the food. Across England and Wales the poor went souling — calling at houses to offer prayers for the household's dead in exchange for spiced soul cakes. That exchange, a performance at the door for something to eat, is the direct ancestor of trick-or-treating.
The Victorians make it a party
By the nineteenth century the religious weight had largely gone and something lighter took its place. Halloween became an evening of games, most of them thinly disguised divination: bobbing for apples, throwing apple peel over the shoulder to read the initial of a future spouse, roasting nuts on the hearth to see whose love would burn steady.
Robert Burns had already put the Scottish version on the page in his 1785 poem Hallowe'en, a catalogue of these rituals performed half-seriously by people who mostly wanted to know who they would marry.
Then it went to America, and came back
Irish and Scottish emigration carried the whole bundle across the Atlantic in the nineteenth century. In America it met mass-produced costumes, a confectionery industry and suburban streets ideal for going door to door — and it grew into the commercial festival we know.
Britain got it back in that form, largely from the 1980s onwards, which is why older people here often insist Halloween is "an American import". It is a fair description of trick-or-treating in its current shape, and completely wrong about the festival itself. The lanterns, the disguises, the door-to-door and the games were all here first. We simply let them lapse — in England, largely because Bonfire Night arrived five days later and took the fireworks, the fires and the children with it.
So why do we celebrate it?
Because the year turns, the light goes, and people have always marked that with fire, disguise and food. Everything else — the sweets, the plastic fangs, the scare mazes — is decoration on a very old and very sensible impulse: to make a party out of the start of winter, and to look the dark in the face while there is still company to do it with.