All Hallows Eve, or Halloween, is the modern name in English for the great north European festival which signalled the end of the light and warm half of the year, and ushered in the cold and dark one, and so divided the season of autumn from that of winter in these northern lands. It was known in Irish as Samhain, summer’s end; in Welsh as Nos Galan Gaeaf, “winter’s eve”; in Anglo-Saxon as Blodmonath, “blood month”; and in Norse as the “winter nights”. As such it was one of the greatest religious festivals of the ancient northern pagan year, and the obvious question is what rites were celebrated then.

The answer to that is that we have virtually no idea, because northern European pagans were illiterate, and no record remains of their ceremonies. The Anglo-Saxon name for the feast comes down to an agricultural reality, the need to slaughter the surplus livestock at this time and salt down their meat, because they could not be fed through the winter. A Christian monk, Bede, commented that the animals were dedicated to the gods when they were killed, but he did not appear to know how (and they would still have been eaten by people).

Nonetheless, we can reconstruct some of the associations of the ancient festival from those which continued to hang about it in the Middle Ages, and from folk customs attached to it, so widespread that they must refer to a generally shared set of ancient attitudes. As a festival positioned on a major boundary in the year, Halloween faced in two different directions.

In one sense it was a time of plenty and homecoming. People would have been well fed after the bountiful summer and autumn seasons, in most years, and be gathering in the home settlement after the time of work and travel. The warriors, traders, sailors and people with skills to offer had all come back, the harvest was in the barns and the flocks and herds had been driven in from the summer pastures and the outfields. It was a time for reunions, stories, celebrations, the settlement of disputes, the taking of stock and the learning of lessons to be applied in the next year, and for relaxation. In medieval Ireland local kings were said to hold a feast at their royal halls, for a week before and after Samhain, for all these purposes.

There was, however, the other face of the festival: that it ushered in winter, the most frightening, uncomfortable and inconvenient of all the seasons in the northlands. Even in modern Britain, it is the time when clocks are changed and the night rushes into the afternoon. It was the feast that prefaced the months of darkness, cold, hunger, claustrophobia and the physical illnesses consequent of all of those. What was coming was the season of death; not just of leaves, flowers and light, but of humans, as more would perish in the winter and early spring than at any other time of year. That was why Halloween was widely regarded as the time when the spirits of darkness and fear, the evil and malevolent forces of nature, were let loose upon the earth.

People reacted to this forbidding prospect in two different ways. One was to make it the festival of divination par excellence, in which humans most frequently tried to predict the future: and in pre-modern times the prediction most often sought was who would live through the winter. The other reaction was to mock darkness and fear, by singing songs about the spirits which personified it (in Wales, for example, the tail-less black sow and the White Lady), or dressing up as them: in other words, to confront boldly the terrors of the season now arriving.

It is commonly asserted that the feast was the pagan festival of the dead. In reality feasts to commemorate the dead, where they can be found in ancient Europe, were celebrated by both pagans and early Christians, between March and May, as part of a spring cleaning to close off grieving and go forth into the new summer. On the other hand, the medieval Catholic church did gradually institute a mighty festival of the dead at this time of year, designating 1 November as the feast of All Saints or All Hallows, initially in honour of the early Christian martyrs, and 2 November as All Souls, on which people could pray for their dead friends and relatives. This was associated with the new doctrine of purgatory, by which most people went not straight to hell or heaven but a place of suffering between, where their sins were purged to fit them for heaven. It was also believed that the prayers of the living could lighten and shorten their trials, as could the intercession of saints (which is why it was good to have all of those at hand). The two new Christian feasts were, however, only developed between the ninth and the twelfth centuries, and started in Germanic not Celtic lands.

The Protestant reformation, which did away with both the doctrine of purgatory and the cult of saints, removed all these rites from most of Britain, and left nothing but a vague sense of Halloween as a time with creepy associations. It survived in its old form in Ireland, both as the Catholic feast of saints and souls and a great seasonal festival, and massive Irish emigration to America in the 19th century took it over there.

In the 20th century it developed into a national festivity for Americans, retaining the old custom of dressing up to mock powers of dark, cold and death, and a transforming one by which poor people went door to door to beg for food for a feast of their own, morphing again into the children’s one of trick or treat. By the 1980s this was causing some American evangelical Christians to condemn the festival as a glorification of the powers of evil (thus missing all its historical associations), and both the celebrations and condemnations have spilled over to Britain.

On the whole, though, the ancient feast of Winter’s Eve has regained its ancient character, as a dual time of fun and festivity, and of confrontation of the fears and discomforts inherent in life, and embodied especially in northern latitudes by the season of cold and dark.