Angolul tudok elonyben:

What is Halloween?

Halloween is an annual celebration, but just what is it actually a
celebration of? And how did this peculiar custom originate? Is it, as some
claim, a kind of demon worship? Or is it just a harmless vestige of some
ancient pagan ritual?

The word itself, "Halloween," actually has its origins in the Catholic
Church. It comes from a contracted corruption of All Hallows Eve.
November 1, "All Hollows Day" (or "All Saints Day"), is a Catholic day of
observance in honor of saints. But, in the 5th century BC, in Celtic
Ireland, summer officially ended on October 31. The holiday was called
Samhain (sow-en), the Celtic New year.
One story says that, on that day, the disembodied spirits of all those who
had died throughout the preceding year would come back in search of
living bodies to possess for the next year. It was believed to be their only
hope for the afterlife. The Celts believed all laws of space and time were
suspended during this time, allowing the spirit world to intermingle with
the living.
Naturally, the still-living did not want to be possessed. So on the night of
October 31, villagers would extinguish the fires in their homes, to make
them cold and undesirable. They would then dress up in all manner of
ghoulish costumes and noisily paraded around the neighborhood, being
as destructive as possible in order to frighten away spirits looking for
bodies to possess.
Probably a better explanation of why the Celts extinguished their fires
was not to discourage spirit possession, but so that all the Celtic tribes
could relight their fires from a common source, the Druidic fire that was
kept burning in the Middle of Ireland, at Usinach.
Some accounts tell of how the Celts would burn someone at the stake
who was thought to have already been possessed, as sort of a lesson to
the spirits. Other accounts of Celtic history debunk these stories as myth.
The Romans adopted the Celtic practices as their own. But in the first
century AD, they abandoned any practice of sacrificing of humans in favor
of burning effigies.
The thrust of the practices also changed over time to become more
ritualized. As belief in spirit possession waned, the practice of dressing up
like hobgoblins, ghosts, and witches took on a more ceremonial role.
The custom of Halloween was brought to America in the 1840's by Irish
immigrants fleeing their country's potato famine. At that time, the favorite
pranks in New England included tipping over outhouses and unhinging
fence gates.

The custom of trick-or-treating is thought to have originated not with the
Irish Celts, but with a ninth-century European custom called souling. On
November 2, All Souls Day, early Christians would walk from village to
village begging for "soul cakes," made out of square pieces of bread with
currants. The more soul cakes the beggars would receive, the more
prayers they would promise to say on behalf of the dead relatives of the
donors. At the time, it was believed that the dead remained in limbo for a
time after death, and that prayer, even by strangers, could expedite a
soul's passage to heaven.

The Jack-o-lantern custom probably comes from Irish folklore. As the tale
is told, a man named Jack, who was notorious as a drunkard and
trickster, tricked Satan into climbing a tree. Jack then carved an image of
a cross in the tree's trunk, trapping the devil up the tree. Jack made a
deal with the devil that, if he would never tempt him again, he would
promise to let him down the tree.
According to the folk tale, after Jack died, he was denied entrance to
Heaven because of his evil ways, but he was also denied access to Hell
because he had tricked the devil. Instead, the devil gave him a single
ember to light his way through the frigid darkness. The ember was placed
inside a hollowed-out turnip to keep it glowing longer.

The Irish used turnips as their "Jack's lanterns" originally. But when the
immigrants came to America, they found that pumpkins were far more
plentiful than turnips. So the Jack-O-Lantern in America was a hollowed-
out pumpkin, lit with an ember.
So, although some pagan groups, cults, and Satanists may have adopted
Halloween as their favorite "holiday," the day itself did not grow out of evil
practices. It grew out of the rituals of Celts celebrating a new year, and
out of Medieval prayer rituals of Europeans. And today, even many
churches have Halloween parties or pumpkin carving events for the kids.
After all, the day itself is only as evil as one cares to make it.