In the United States, Halloween falls on October 31. The following day, November 1, is All Saints' Day in the Christian church calendar. Hallow is an archaic word for sanctify, or make holy, and eve refers to the evening before an important festival, as in Christmas Eve and New Year's Eve. So October 31 was known as the Eve of All Hallows, which became All Hallows' Eve, which became All Hallow Even, and was shortened to Hallowe'en, and eventually Halloween.

In the ancient Celtic calendar of pre-Christian Britain, the New Year began on November 1, and the night before was Old Year's Night. This was the night when Samhain, or Samhuin, the Celtic Lord of Death, called together the souls of the wicked who had died during the past year. In parts of Ireland, the night of October 31 is still known as Oidhche Shamhna, the Vigil of Samhain. Great fires were lit in defiance of winter's darkness-they were known as Samhain Fires, and they were the origin of the great bonfires that still blaze in England on "Bonfire Night." This is held a few days later, on November 5, to coincide with the date that Guy Fawkes and his co-conspirators failed to blow up the English Houses of Parliament in 1605, but it is clearly part of the same ancient festival. An effigy of the unfortunate Fawkes is burned on the bonfire, just as the ancient Celts made symbolic sacrifices to Lord Samhain by burning dolls and images of the wicked on their own great fires.

Old Year's Night was a night of great revelry. Samhain was seen as a kind figure but also powerful. The ancient Celts felt that he should be respected. They offered gifts of food and drink to Samhain and danced and sang in his honor. The Celts dressed up as witches and demons, to make fun of the souls of the wicked as they imagined them making their way across the dark land toward their final resting place. Lanterns with comical, grotesque faces were carved out of hollowed-out vegetables and hung outside houses to ward off evil-in the same spirit that made medieval craftsmen decorate church towers with grotesque demons, known as gargoyles.

The early Catholic Church sought to end this pagan revelry. In the seventh century, Pope Boniface IV introduced All Saints' Day to replace the Celtic festival of the dead. The old pagan beliefs of the Celts died out, or went underground, but the old rites and rituals clung hard. They were tied to the natural rhythms of the year: winter, summer, seed-time, harvest. The Eve of All Hallows in many ways retained its old character as a time when people defied the darkness of the approach of winter by lighting great fires.

Many of the rituals that we still perform are echoes of something ancient. In the United States, people make pumpkins into jack-o'-lanterns with grotesque faces-in Britain they do the same thing with turnips. People still wear masks. Trick or treat evolved from the Celtic practice of giving food in exchange for blessings from the spirits of the dead. In parts of Scotland, Halloween is still a time when "bogles, witches, and whigmaleeries" ride through the air. Scottish children still paint their faces and dress up in extravagant costumes, to go from house to house as "guizers," dancing and singing in exchange for food. Bobbing for apples is an outgrowth of a Celtic ritual, where an apple would be placed in a tub of water or suspended on a string, and the first person to bite it would be the next one to marry. In Celtic mythology, the dead inhabit a "Paradise of Apples" known as the Emhain Abhlach, and apples would be offered to them to insure a blissful immortality. Bonfires are still lit at Halloween, just as the Celtic villagers of ancient times extinguished all other fires on Old Year's Night and then relit their hearths from one great shared flame, bonding all families of the village together.

In Mexico people have a celebration that honors friends and relatives who have died, called Los Dias de los Muertos-the Days of the Dead. It occurs on November 1 and 2. At home, families make an altar in honor of their relative set with marigolds and his or her favorite foods, as well as special sweet breads decorated with edible "bones." They might also sing and play the favorite music of their loved one. In some regions, family and friends walk together in a procession to the cemetery. They sit around the grave and place the altar of marigolds, foods, and sweet breads atop the grave. They share the favorite music of the dead or pay a passing Mariachi band to play. Some people stay all night, from November 1 to November 2, sharing stories from the life of the deceased. In Mexican cities during Los Dias de los Muertos, imitation skeletons are used to make fun of death, with the idea that all must die and we should laugh now and enjoy life while we can. One might see a Mariachi band with players made of wooden skeletons or a barber shop with skeletons propped in chairs, ready for a shave or a haircut.

In the United States, Halloween is a time for parades, parties, dressing up, and having fun. It's a festival for children-though of course, adults join in. But it is useful to remember that as they go from door to door trick-or-treating, children are continuing a tradition that stretches back into ancient times.