Even in ancient times, Halloween was a festival for witches, goblins, and ghosts, as well as for lighting bonfires and playing devilish pranks.

What has changed over the centuries are the reasons for dressing up ghoulishly, lighting fires, and acting mischievous. Now these things are done for fun -- and by children; in the past, they were done in deathly earnest - and by adults.

Named "All Hallows Eve," the festival was first celebrated by the ancient Celts in Ireland in the fifth century B.C. On the night of October 31, then the official end of summer, Celtic households extinguished the fires on their hearths to deliberately make their homes cold and undesirable to disembodied spirits. They then gathered outside the village, where a Druid priest kindled a huge bonfire to simultaneously honor the sun god for the past summer’s harvest and to frighten away furtive spirits.

The Celts believed that on October 31, all persons who had died in the previous year assembled to choose the body of the person or animal they would inhabit for the next twelve months, before they could pass peacefully into the afterlife. To frighten roving souls, Celtic family members dressed themselves as demons, hobgoblins, and witches. They paraded first inside, then outside, the fire less house, always as noisy and destructive as possible. Finally, they clamored along the street to the bonfire outside town. A villager, deemed by appearance or mannerism to be already possessed, could be sacrificed in the fire as a lesson to other spirits contemplating human possession.

The Romans adopted Celtic Halloween practices, but in A.D. 61 they outlawed human sacrifice, substituting the Egyptian custom of effigies (called ushabti by the Egyptians, who buried scores of statuettes with a pharaoh in place of his living attendants, once entombed with their king). In time, as belief in spirit possession waned, the dire portents of many Halloween practices lightened to ritualized amusement.

Irish immigrants fleeing their country's potato famine in the 1840s brought to America with them the Halloween customs of costume and mischief. The favorite pranks played by New England Irish youths on "mischief night" were overturning outhouses and unhinging front gates.

It was also the Irish who originated the term jack-o'-lantern, taken from Irish folklore. As the legend goes, a man named Jack, notorious for his drunken ways, tricked the devil into climbing up a tree. Quickly carving a cross into the tree's trunk, Jack trapped Satan until he swore he’d never again tempt Jack to sin. Upon his death, Jack found himself barred from the comforts of heaven for his repeated sinning, and also refused entrance to the heat of hell from an unforgiving Satan. Condemned to wander in frigid darkness until Judgment Day, he implored the devil for burning embers to light his way. Though Satan had embers in surplus, he allotted Jack a single coal that would last an agonizingly short time. Putting the ember into a turnip he had chewed hollow, he formed jack’s lantern.

Trick or Treat. The most widely accepted theory on the origins of trick-or-treating traces the practice to the ninth-century European custom of "souling."