The origins of Halloween have been traced to Middle Ages Europe and included sacrifices to gods and more harmless practices involving costumes and going door-to-door for hand-outs.
The name "Halloween" is an early Middle Ages term that represented the day before All Hallows Day, or All Saints Day. This Catholic holiday on Nov. 1 commemorating Christian saints and martyrs has been observed since the early Middle Ages, according to About.com.
Customs attributed to Halloween include Jack-O-Lanterns, which date back centuries. Souling, which involved going door-to-door and offering prayers for the dead in exchange for "soul cakes" and other treats, was a part of the holiday in the Middle Ages.
A custom called Mumming, or "guising," was initially associated with Christmas and involved parading in costume and chanting rhymes.
Today's emphasis on children is different from the origins of Halloween. More than 2,000 years ago the holiday was a New Year's Eve celebration on Oct. 31 by Celtic people living in what later became Great Britain and northern France, reported London Free Press.
During their pagan festival of Samhain participants celebrated the end of the harvest. They also believed spirits rose from the dead and caused mischief.
What we have in the 21st century is actually a wide-ranging mix of ancient paganism, Catholicism, commercialism and other practices, according to Nicholas Rogers, a cultural historian at York University in Toronto. Rogers is the author of "Halloween: From Pagan Ritual to Party Night."
"A lot of the rituals and traditions associated with those early modern festivals have been amended but continue to persist," he told London Free Press.
Trick-or-treating resembles the Medieval practice of "threshold encounters," when poor folk went to the homes of rich people on All Souls' Day asking for food and drink in return for prayers for the dead, explained the London Free Press.