Short answer: Halloween is not purely pagan and not purely Christian. It is a stack. The date and the mood come from Samhain, the Gaelic festival that closed the harvest and opened winter, described in the Irish sources as the night the boundary with the Otherworld thins. The name comes from the church calendar: All Hallows' Eve, the evening before All Saints on 1 November. Most of what you actually do on 31 October, pumpkin included, was assembled in North America in the last 150 years. And the line everybody repeats, that Samhain was a Celtic god of the dead, is false.
Samhain, and how sure we can be
Samhain (pronounced roughly "sow-in") was one of the four Irish quarter days, with Imbolc, Beltaine and Lughnasa. It sat at the start of November: harvest in, herds down from the hills, the dark half of the year beginning. A hinge, and hinges in Irish myth are dangerous places to stand.
The stories agree. The Second Battle of Mag Tuired, where the Tuatha De Danann break the Fomorians, is fought at Samhain. In the tale of Nera, a man walks out of Cruachan on Samhain night on a dare and finds the sidhe mound standing open. Cu Chulainn's adventures keep starting on it. The pattern holds across texts with nothing else in common: this is when the mounds open and the Otherworld is abroad.
Here is the caveat almost nobody offers you. All of those texts were written down by Christian monks, centuries after the last person kept the festival as a religious act. We are reading medieval literature about a remembered pagan past, not pagan liturgy. That the date mattered is well attested. What Iron Age people did on the night is inference, and careful scholarship says so out loud.
The distinctive part is the Otherworld itself. Tir na nOg, the sidhe: not an afterlife you earn by dying, but a place next door, reached through a mound, a mist or a lake. Hades, the Duat and Hel all require you to be dead first. Samhain is the night the door is unlatched for the living too.
The Christian layer, then the American one
In the 9th century the Western church fixed All Saints' Day on 1 November, with All Souls, for the ordinary dead, on 2 November. "All Hallows' Eve" is the evening before, contracted in Scots into Hallowe'en. Whether the church put it there deliberately to sit on top of Samhain is genuinely debated: the date moved first in Rome and Frankish territory, not in Ireland, which weakens the tidy version. Debated is solid. Deliberate is guessing.
Disguise is the strongest surviving thread. Mumming and guising are documented in Scotland and Ireland: going house to house in costume, offering a rhyme, receiving food. That is the direct ancestor of trick or treating, and it crossed the Atlantic with Irish and Scottish emigration in the 19th century, above all after the Famine.
America gave it a better prop. Ireland carved turnips and beets; the pumpkin is a New World plant, bigger and easier to hollow, and it won on merit. The lantern brought an Irish tale with it: Stingy Jack tricked the devil, was refused by heaven and hell alike, and walks the roads with a coal in a carved turnip. Jack of the lantern. Trick or treating in its modern shape is a 20th-century North American invention that spread in the 1930s and 1940s and was then exported back across the ocean. When a European city grumbles about an American import, it is half right: the custom came back from America, but it left from Ireland.
What came from where
| Halloween custom | Where it actually comes from | How sure we are |
|---|---|---|
| The date, 31 October into 1 November | Samhain, the Gaelic start of winter | Well attested |
| The dead being close | Samhain's thin boundary, plus Christian All Souls | Well attested, both layers |
| Costumes, house to house | Mumming and guising in Scotland and Ireland | Well documented, later than the pagan period |
| The name "Halloween" | All Hallows' Eve, contracted in Scots | Certain, plain etymology |
| The jack o' lantern | Irish turnip lanterns and the tale of Stingy Jack | Likely, folklore rather than record |
| The pumpkin | North America, where pumpkins grow | Certain |
| Trick or treating as we know it | United States and Canada, 1930s and 1940s | Certain |
| Bonfires | Samhain and Beltaine fires in Ireland and Scotland | Likely |
| Witches on broomsticks | Early modern witch trials, not Celtic religion | Well attested, wrong century entirely |
| "Samhain, god of the dead" | Nothing at all | 19th-century invention |
Quick questions
Is Halloween a pagan festival?
Partly, and the layers do not cancel each other. The date, the darkness and the nearness of the dead are pre-Christian and Gaelic. The name and the two-day structure are medieval Christian. The costumes are folk custom from a Christian era. The pumpkin, the candy and the doorbell are modern American. Halloween descends from Samhain the way a language descends from an older one: real ancestry, not the same thing.
How do you pronounce Samhain?
Roughly "SOW-in", the first part rhyming with cow. The mh in Irish sounds like a w, so there is no "ham" in it. Scottish Gaelic Samhainn lands closer to "SAV-in". In modern Irish the word is still the name of the month of November.
Was Samhain a god?
No. No Irish source knows a god of that name. The word means the festival, probably something like "summer's end". The claim comes from 18th and 19th-century antiquarians who assumed a festival name had to be a deity's name, and 20th-century pamphlets warning parents about Halloween multiplied it. For a real goddess of night and witchcraft, see Hecate, and for the symbols people wear this time of year.
Celtic myth is on the list for MythologyNow, not in it yet. What is there now is Greek, Norse and Egyptian, narrated like short films: the gods and the myths. If October has you in the mood, start with Thanatos or the monsters.
