Before pumpkins, plastic skeletons and buckets full of candy, there was Samhain.

Halloween has become an enormous cultural and commercial phenomenon, but many of the traditions we associate with October 31st have much older roots. In Ireland, the season is intertwined with Samhain, the cross-quarter day Gaelic festival that marks the end of the harvest season and the midpoint between the Autumn Equinox and the Winter Solstice. 

Over the years, the popularity of Halloween has grown exponentially. It has spawned a multi-billion dollar industry which includes movies, costumes, tricks-or-treats and haunted attractions, yet few of its passionate celebrants understand the holiday’s ancient origin. Here are 13 things to know about its Celtic roots to keep you up at night.

Samhain (rhymes with COW-in🐮) lines up with October 31st and November 1st.  It is one of the eight Gaelic festivals commemorated in the Wheel of the Year, a modern paganism celebration of seasonal changes including both solstices, both equinoxes and the midpoints between them all.  Falling between the autumn equinox and the winter solstice, Samhain marks the time when darkness overtakes the light.

Like most cross-quarter day festivals, Samhain begins on the preceding evening at dusk on October 31st and ends at sundown on November 1st. October 31st is Oíche Shamhna, or Samhain Eve, which eventually became intertwined with what we know today as Halloween. 

The other three cross-quarter day festivals (marking the midpoint between solstices and equinoxes are Imbolc (February 1-2), Beltane (May 1-2) and Lughnasadh (August 1-2). 

Samhain has particularly strong associations with Ireland and Scotland, where the Scottish Gaelic forms include Samhuinn and Samhainn. Related autumn traditions can also be found elsewhere in the Celtic lands, including Calan Gaeaf in Wales, Hop-tu-Naa on the Isle of Man, Kalan Gwav in Cornwall and Kalan Goañv in Brittany.

Several Irish Neolithic monuments were positioned to interact with the sun around the cross-quarter days between the equinoxes and solstices. The Mound of the Hostages (Dumha na nGiall) at the Hill of Tara, for example, is illuminated by the rising sun around the time of Samhain and Imbolc.

These remarkable solar alignments suggest that this turning point in the seasonal year held significance in Ireland thousands of years before the historical Celtic period.

In later Irish folklore, Samhain was a time when the ordinary boundaries between this world and the Otherworld were thought to be at their thinnest. The Aos Sí, supernatural beings in Irish folklore (aos = people, sí = fairy mound), were believed to be particularly active during this time.

The dead might also return to their former homes.  Families sometimes prepare large meals, keep their doors open and leave empty seats at the table so that dead ancestors could visit and have a chat with their living relatives. Precautions, however, were taken against less welcome supernatural visitors.

For one night, tradition warns us to be a little more careful about who (or what) was knocking at our door.

The wearing of costumes (also called mumming or guising) is believed to serve the purpose of blending in with spirits or Aos Sí.  Masks and disguises fit naturally into a night populated in folklore by spirits and supernatural beings. Some later interpretations suggest that disguising oneself offered protection or allowed the wearer to blend in with wandering spirits.

In Ireland and Scotland, traditions of guising involved people dressing in disguise and traveling from house to house, often performing songs, rhymes or other entertainment in exchange for food or treats.

Long before fun-size candy bars filled plastic pumpkins, food was already an important part of Halloween traditions.

In Ireland and Scotland, costumed visitors known as guisers traveled from house to house, often performing a song, rhyme or other bit of entertainment in exchange for food, nuts, fruit or other treats. Hospitality was especially meaningful during a season associated with supernatural visitors and the beginning of the difficult winter months.

Another angle? Dressing in costume and going door to door in song, it was thought that the bribe of treats would appease the spirits and they would not kill your livestock during the long winter. 

Mischief had long been part of Halloween celebrations when Irish and Scottish immigrants brought their traditions to North America. By the late 19th and early 20th centuries, Halloween in the United States had become a favorite night for pranks, from soaping windows to tipping over outhouses and generally making a nuisance of oneself.

The phrase “trick or treat” began appearing in North America in the 1920s, and trick-or-treating became increasingly popular in the United States after World War II.

While vandalism associated with Halloween dropped dramatically over the years, the idea that those who gave treats would be spared damage to property is clearly a throwback to appeasing wandering spirits for protection.

Before there were pumpkins, there were turnips. In Ireland and other parts of the British Isles, turnips and similar root vegetables were hollowed out, carved with frightening faces and illuminated from within. Ireland's National Museum even preserves a plaster cast of a traditional “ghost turnip” associated with Halloween customs in County Donegal.

One popular folktale tells of “Stingy Jack,” a dishonest man who repeatedly tricked the Devil. After Jack died, he was accepted into neither heaven nor hell and was condemned to wander the earth carrying a burning ember inside a hollowed-out vegetable to light his way.

When Irish immigrants brought their Halloween traditions to North America, they encountered pumpkins — larger, softer and considerably easier to carve than a turnip

Halloween wasn't all spirits, trick and treats. It was also an excellent opportunity to find out who you were going to marry.

Apples and nuts featured prominently in traditional Irish Halloween games, many of which involved divination and predicting the future.

Young people bobbed for apples floating in tubs of water or attempted to bite apples suspended from strings. Other games used apple peels, nuts or other foods to predict romance, marriage or good fortune in the coming year.

Samhain is frequently described today as the “Celtic New Year.” The historical reality is a bit more complicated but November 1st clearly marked an important moment in the traditional Irish seasonal calendar.  It was the closing of one agricultural cycle and the beginning of another season.  It signaled the arrival of winter and the dark half of the year

Livestock were brought down from summer pastures, harvest work was ending and communities prepared for the difficult months ahead.

The timing also had practical implications. Traditionally, this was the time when livestock that could not be supported through the winter might be slaughtered. The colder weather made it an ideal time for the killing and preservation of meats and fowl.

Halloween did not develop from a single ancient festival. It accumulated layers over many centuries.

Over time, Christian commemorations of the dead existed alongside and became intertwined with older seasonal customs, local folklore and traditions involving spirits, fires, food, divination and disguise.

Christian observances honoring saints and the dead eventually became associated with the beginning of November. November 1st became All Saints' Day (or All Hallows' Day) followed by All Souls' Day on November 2nd.  The evening before All Hallows' Day was therefore All Hallows' Eve which was eventually shortened to Halloween.

As in many other ancient celebrations, fire played an important role in traditional Samhain and Halloween observances. To symbolize the end of the year, home fires were extinguished.  Some legends claim that soot and ash from these fires were used to coat the skin as a means of protection.

Communal bonfires marked the transition into winter and the growing season of darkness, strengthening the community as the cold and challenging months approached. It is often said that from these fires, personal hearths were relit for the New Year. 

Bonfires remained part of Irish Halloween celebrations for generations and, in some places, continue to be associated with the night today.

While there is some indication that All Hollows' Eve was recognized by early Anglican and Catholic settlers, it was the mass exodus from Ireland (during and after the Great Hunger) that Halloween/Samhain was introduced on a large scale to the Americas.

Irish immigrants brought traditions involving Halloween games, fortune-telling, disguises, supernatural folklore and seasonal gatherings to North America. Scottish immigrants brought related traditions as well. Once in North America, these customs mixed with traditions from other immigrant communities and gradually evolved.

The first record of children dressing up and going door to door for treats comes from Kingston, Ontario, Canada in 1911. This continued into the 20th century with children dressing in costume and visiting neighboring homes, eventually developing into the modern practice of trick-or-treating.

Ancient traditions have a way of finding new life in popular culture, and Samhain is no exception. The Halloween film franchise makes several references to it. In Halloween II (1981), Michael Myers writes “Samhain” on a school chalkboard (although Dr. Loomis famously pronounces the word phonetically as “Sam-hain.”)  Samhain plays an even larger role in Halloween III: Season of the Witch (1982), in which antagonist Conal Cochran (who happens to be Irish) exaggeratedly proclaims, “Halloween….the festival of Samhain! The last great one took place 3,000 years ago when the hills ran red with the blood of animals and children.”

In music, Glenn Danzig founded the 80s rock band Samhain after his departure from The Misfits, penning themed songs such as Halloween II and November-Coming-Fire.

Needless to say, horror movies and rock music should probably not be considered reliable sources for ancient Irish history. But they certainly helped keep the name Samhain alive in popular culture.