Every autumn the same paragraph makes the rounds. The ancient Celts celebrated their New Year at Samhain, the night when the veil between the living and the dead grew thin, and the Church, unable to stamp it out, renamed it All Hallows' Eve.

Parts of that story are true. Samhain was real, it fell at the start of November, and it left its mark on Halloween. But the claims about a Celtic New Year and a pagan feast of the dead rest on thin evidence, and much of the familiar version was assembled by Victorian scholars rather than handed down from the Iron Age.

What the oldest records say

Samhain, in Old and Middle Irish Samain, was the festival held on 1 November in medieval Ireland. Because the Gaelic day was reckoned from sunset, the celebration began on the evening of October 31. The name survives as the Irish and Scottish Gaelic word for November.

The earliest firm evidence is practical rather than mystical. Glosses in the Senchas Már, an Irish law collection of the 7th to 8th centuries, note that cattle were driven out to summer pasture around May Day and brought back around November Day. Bettina Arnold, co-director of the Center for Celtic Studies at the University of Wisconsin-Milwaukee, described Samhain in a 2001 lecture as the moment herds were culled, crops stored and fishing boats beached for repair. Irish law tracts, she notes, name the food carried to a lord before Christmas as "the Samhain pig."

Samhain appears in the earliest Irish literature, from the 9th century. The tenth-century tale Tochmarc Emire lists it first among the four seasonal festivals. Serglige Con Culainn says the Ulster festival lasted a week, with meetings, feasting, drinking and contests. The sources disagree on details: Echtra Cormaic places the Feast of Tara at every seventh Samhain, while Geoffrey Keating, writing in the early 1600s, says every third.

A season for stories

Medieval storytellers loved the date. Aillen, a fire-breather from the Otherworld, burns the palace of Tara each Samhain until the young Fionn mac Cumhaill stays awake and kills him. In Echtra Neraí, Nera ties a band around a hanged man's ankle on Samhain night, carries the corpse off in search of a drink, and follows a fairy host into the Otherworld. The Second Battle of Mag Tuired and the Táin Bó Cúailnge both begin at Samhain.

All of this was written down by Christian monks long after Ireland's conversion, and Ronald Hutton has pointed out what is missing. Of pagan religious observances, he wrote in The Stations of the Sun (1996), "none of the tales ever portrays any." The only historical reference to pagan rites comes from Keating, who claimed that druids lit a sacred fire at Tlachtga, the Hill of Ward in County Meath, and that every other fire was put out and relit from it. Keating died in 1644, and his source is unknown. Hutton suggests the royal assemblies of Samhain simply made a good stage for drama, much as Arthurian tales are set at court gatherings at Christmas. Writing in The Guardian in 2014, he was blunter: about the ancient rites, "we have virtually no idea."

How it became the Celtic New Year

The phrase "Celtic New Year" has authors. In the late 19th century Sir John Rhys argued, from folklore in Ireland and Wales and from Manx speakers who sometimes called October 31 "New Year's Night," that Samhain had begun the Celtic year. Sir James Frazer popularized the idea and added a second: that Samhain had been the pagan festival of the dead, Christianized as All Saints and All Souls. In a 2024 paper in the journal Folklore, Hutton traces both beliefs, an orthodoxy by the start of the 21st century, to these two scholars, while noting that the New Year element had older origins.

Writers who followed Frazer took up the theme. J. A. MacCulloch stated flatly that "the great commemoration of the dead was held on Samhain eve." Clement Miles was more careful. He wrote that the Celtic year apparently began about November 1, then conceded, "It is impossible to fix precise dates."

The Coligny problem

The strongest card for the New Year theory is a bronze calendar plaque found at Coligny in France in the late 19th century. Engraved in Gaulish in Roman Gaul, it is usually dated to the 2nd century CE. It includes a month called SAMON, apparently related to Samain, and the 17th day of that month carries the note TRINOX SAMONI, "the three nights of Samon." Arnold, like many writers, reads it as placing Samonios at the beginning of the year.

The details are less decisive. The traditional etymology links the word to a root meaning "summer," an odd name for a festival that opens winter, while Xavier Delamarre and Ranko Matasović propose a Proto-Celtic word for "assembly." And the three nights of Samon could mark an early November festival or possibly the summer solstice.

Hutton's verdict, quoted by the BBC, is that "the medieval records furnish no evidence" that 1 November was a major pan-Celtic festival. Steve Roud, author of a guide to British superstitions, agrees that Samhain was by far the most important quarter day in Ireland, but notes that in Wales 1 May and New Year took precedence, and in Scotland it is hardly mentioned until much later.

Did the Church take it over?

The chronology of All Saints' Day is messier than the conversion story. In 609 Pope Boniface IV fixed 13 May as a holy day for all the martyrs. By 800, churches in Ireland and Northumbria kept a feast of all saints on 1 November, and the Frankish Empire adopted that date in 835. All Souls' Day on 2 November became established in the 11th century.

Nicholas Rogers, quoted by the BBC, notes that Ireland commemorated the saints on 20 April, "a chronology that contradicts the widely held view" that November was chosen to Christianize Samhain. Hutton argues that the November feasts started in Germanic, not Celtic, lands, and that ancient European festivals of the dead tended to fall between March and May. Frazer read it the other way. The safest summary is that Samhain and All Hallows probably shaped each other.

What survived

The richest material is also the most recent. Mumming and guising were first recorded in 16th-century Scotland, and pranks on the night appear in the Highlands as far back as 1736. In 18th-century Ochtertyre, a stone for each person was set around the bonfire, and anyone whose stone was disturbed by morning was expected not to live out the year. Carved turnip lanterns lit the way for guisers in 19th-century Ireland and the Scottish Highlands. A Connemara priest, quoted by Arnold, recalled that after November Eve "the fairies pass over all such things and make them unfit to eat," so as boys they gorged on blackberries on the last day of October.

These customs may preserve something very old, or they may be centuries of accretion around a date that mattered to farmers. What crossed the Atlantic with Irish and Scottish emigrants in the 19th century was this folk Halloween of turnip lanterns, divination games and disguised visitors at the door, not a druid rite. The oldest secure Irish evidence for the festival itself is a legal note about bringing the cows home.