The vast majority of the traditions commonly associated with Halloween today are borrowed or adapted from four different festivals, namely:

• The Roman Feralia festival, commemorating the dead
• The Roman Pomona festival, honoring the goddess of fruit and trees
• The Celtic festival Samuin, meaning “summer’s end”, (also called “Samhain”) which the bulk of Halloween traditions ultimately stem from
• The Catholic “All Soul’s Day” and “All Saints’ Day”, which was instigated around 800 by the Church to try to replace Samuin

The practice of wearing costumes or masks during this sort of end of Autumn celebration comes from a Celtic end of year (they celebrated their New Year on November 1) Samuin tradition.  During Samuin, young men impersonating evil spirits by dressing up in white costumes with blackened faces or masks.  It was believed that during the transition from one year to the next, the realms of the living and the dead would overlap allowing the dead to roam the Earth again.  Thus, by dressing up as spirits, they were trying to fool actual spirits into thinking they were as well, which is particularly helpful when encountering evil spirits.

Beginning in the 8th century, the Catholic Church was trying to provide an activity that would hopefully stamp out the old Samuin traditions.  They came up with “All Hallows Even (evening)”, “All Soul’s Day”, and “All Saints’ Day”.  Many of the traditions of Samuin were then adapted into these festivities and by the 11th century, the Church had adapted the Celtic costume tradition to dressing up as saints, angels, or demons during this celebration.

As for the trick or treating, or “guising” (from “disguising”), traditions, beginning in the Middle-Ages, children and sometimes poor adults would dress up in the aforementioned costumes and go around door to door during Hallowmas begging for food or money in exchange for songs and prayers, often said on behalf of the dead.  This was called “souling” and the children were called “soulers”.

An example of a relatively recent (19th century) souling song is as follows:

A soul! a soul! a soul-cake!
Please good Missis, a soul-cake!
An apple, a pear, a plum, or a cherry,
Any good thing to make us all merry.
One for Peter, two for Paul
Three for Him who made us all.

As you might have guessed from the song, a common food given while souling was a Soul Cake (also sometimes known as a Harcake).  Soul cakes were small round cakes, often with a cross marked on top, that represented a soul being freed from Purgatory when the cake was eaten.  Soul cakes were generally sweet cakes, including such ingredients as nutmeg, ginger, cinnamon, and raisins.

Souling ultimately gave rise to guising in the U.K. starting in the 19th century, with children dressing up and begging for things like fruit and money.  In order to earn this token, they’d often tell jokes, sing songs, play an instrument, recite a poem, or perform in some other way for the amusement, not unlike the old tradition of souling but instead of prayers, a performance was offered.

The practice of guising made its way to North America, probably brought over by the Scottish and Irish in the late 19th or early 20th century (first documented reference in 1911).

Trick or treating instead of guising on Halloween popped up in North America in the 1920s and 1930s, first in the western half of the continent. The term and the practice slowly spread, with a brief respite during WWII.  After the WWII sugar rations were lifted, Halloween’s popularity saw a huge spike and within five years trick or treating was a near ubiquitous practice throughout North America.

Once guising morphed into trick or treating, children no longer performed for treats, but instead vandalized and extorted for their confectioneries.  The earliest known reference to “trick or treat”, printed in the November 4, 1927 edition of the Blackie, Alberta Canada Herald, talks of this,

Hallowe’en provided an opportunity for real strenuous fun. No real damage was done except to the temper of some who had to hunt for wagon wheels, gates, wagons, barrels, etc., much of which decorated the front street. The youthful tormentors were at back door and front demanding edible plunder by the word “trick or treat” to which the inmates gladly responded and sent the robbers away rejoicing.

Trick or treating has since spread to parts of the U.K., beginning around the 1980s.  Although, this adapted form of guising has met with a lot of resistance in the last few decades since hopping the pond, often seen by the older generations as “yet another unwanted consumerist culture import from the United States.”  In fact, even as recently as 2006, according to Norwhich Union Insurance, nearly 58% of homeowners in Britain turn off their house lights and pretend no one is at home on Halloween.  One British man went so far as to say about trick or treaters,  “I’ve thought about removing the cover from my doorbell so they electrocute themselves.”

Bonus Facts:

• In parts of Mexico, rather than saying the Spanish equivalent of “trick or treat”, “dulce o travesura” (literally “candy or mischief”), it is common to say ¿Me da mi calaverita? (“Can you give me my little skull?”)
• During Samuin, it was also traditional to leave a place and food at the table for deceased loved ones temporarily returned from the grave.
• The word Halloween originally came from the Middle English ‘Alholowmesse’, meaning “All Saints’ Day”.  The night before Alholowmesse was called “All Hallows Even (evening)” which was eventually shortened to “Hallowe’en” until it just became “Halloween” in the 20th century.
• In North America alone around $3 billion is spent on Halloween costumes.
• Haunted house attractions bring in about half a billion dollars annually.
• Halloween candy sales average around $2 billion per year in the United States.  Chocolate candy bars are consistently ratedas the #1 treat to get, with the Snickers candy bar being most preferred.  In addition, Reese’s peanut butter cups and candy corn are among the most sold Halloween candy items.
• Over 35 million Halloween cards are given every year, producing close to a gross of $100 million.
• As you might have guessed from these numbers, Halloween is the second most commercially successful holiday world-wide after Christmas.
• Around 35 million children in the U.S. between 5 and 13 years old go trick or treating every year, which is around 90% of all children in that age group.
• Around 50% of adults in the U.S. will dress up for Halloween and about 67% will attend a Halloween party or go trick or treating with their children.
• If you’ve read Shakespeare’s  Two Gentlemen of Verona, you might have recalled him mentioning the Hallowmas practice of begging door to door.
  • VALENTINE: Why, how know you that I am in love?
  • SPEED: Marry, by these special marks: first, you have learned, like Sir Proteus, to wreathe your arms, like a malecontent; to relish a love-song, like a robin-redbreast; to walk alone, like one that had the pestilence; to sigh, like a school-boy that had lost his A B C; to weep, like a young wench that had buried her grandam; to fast, like one that takes diet; to watch like one that fears robbing; to speak puling, like a beggar at Hallowmas…
• Starting in the 1950s, UNICEF began distributing small boxes and bags to kids to take around with them while they trick or treat.  The kids would then try to solicit donations for UNICEF from people they were also getting treats from. UNICEF has used this program to collect about $167 million and counting.
• *Warning: there be 3am induced, slightly incoherent ranting right ahead!* 😉
• An alternative form of trick or treating has recently popped up called “Trunk or Treat”, where many people will gather in a parking lot with their trunks open, often decorated, and the children will walk from car to car to get their treats from the trunks.  This is purported to be a safer way to do trick or treating than having kids go door to door, no doubt by the same parents who lobby for the removal of monkey bars from playgrounds due to that, apart from being pretty much the most amazingly fun thing in the world if my childhood memories serve me, they are also a safety hazard.  Get out the helmets and bubble wrap! 😉
• The other major generally put forth reason for this style of trick or treating is that it’s quicker and easier on the parents than walking or driving their kids around… Trunk or Treating parents who are doing it for this particular “benefit”, remember when you were a kid running around neighborhoods with your friends trick or treating?  Remember how awesomely fun that was, not just from getting candy, but from the whole experience that only comes once a year and only for a small number of years before you’re too old?  This doesn’t need to be shortened to a quick parking lot experience where you step five feet in between candy deposits, with the trick or treating done in less time than it takes to watch an episode of SpongeBob.
• Granted, in remote areas where trick or treating isn’t even remotely *pun intended* practical, trunk or treating is far superior to nothing.  It is also certainly more enjoyable for parents who can double the trick or treating with having an adult party at the same time, rather than having to miss out.  And during this time, kids can play and be given games to amuse themselves with, once they’re done making the rounds with the cars, so I’m sure they have fun.  But kids can play games and play with one another anytime.  They only get to trick or treat once a year and only for a small number of years.  Perhaps I’m just being overly nostalgic or being maudlin about the fact that there were a few years in there where a certain parent *looks at my mother* 😉 decided we should attend similar events to this new “trunk or treating” rather than go trick or treating… Although, my wife only once got to go trick or treating (she had to sneak out as an older teenager to do it, probably too old to go trick or treating normally) and she tells me she very much regrets the fact that she never got to do this as a kid. So, from the both of us, don’t rob your kids of this experience.  It’s just great fun and something you can only do as a kid (at least only do without it being totally awkward). 🙂
• While I’m on a sleep deprived soapbox, you know what else kids on the whole don’t seem to get to do anymore which was ridiculously fun?  Neighborhood scavenger hunts! These, often by necessity, included going door to door with no parental supervision.  It was a blast.  Although, looking back at how often said hunts ended up with 6-9 year old me in numerous random strangers houses while they searched for some particular item I requested, I can totally see why that’s not a thing anymore.  But still, super fun at the time. *end rant* 😉