As the cold weather begins to bring in the colorful array of leaves and pumpkin carving, it also brings a holiday of sinister spookiness: Halloween. From small children trick-or-treating to adults just dressing up for fun, Halloween has been a celebrated tradition in Western culture for about 2000 years.

But the pop culture tradition of Halloween has not always been merely a secular, just-for-fun-event. In fact, the origins of Halloween come from a much deeper meaning rooted in spiritual and religious beliefs. About 2,000 years ago, the Celts celebrated what is called “Samhain” on Oct. 31. This festival celebrated the end of the year and is the very earliest origin of what we now call Halloween.

During this day, it was said that the veil separating the living and the dead was opened, and spirits freely roamed the Earth. The popular tradition of Halloween costumes came from the Celtic tradition of wearing masks and other such sinister clothing to scare away evil spirits.

The Celts also believed that fairies freely wandered on Samhain. Although the Celts did not believe fairies to be evil, they did believe them to be creatures of mischief. The earliest “trick-or-treaters” were said to be the fairies, dressed in beggar garb. If the household the fairies approached did not give them food or a “treat,” the fairies were believed to punish the household with mischievous tricks.

Along with the traditions of costumes and trick-or-treating the tradition of pumpkin carving also started in Celtic legend. Celtics told the story of a man named “Stingy Jack”, and, according to legend, Jack trapped the devil in the high branches of a tree by cutting crosses into its trunk. The devil made a deal with Jack that if he let him down then Jack would not be allowed in to hell. But because of Jack’s long life of treachery, he was also denied entrance into heaven.

Therefore, Jack was left to roam the earth for eternity with a carved turnip lantern to guide the way. Because of this legend, the Celts carved turnips (which soon became pumpkins) and placed candles in the turnips to make lanterns. During the first century, after the Romans conquered the Celts, Roman culture began to integrate itself into Celtic traditions. The tradition of bobbing for apples, for example, may have evolved from the Roman holiday celebrating the goddess Pomona, who was the goddess of fruit and trees and whose symbol was an apple. Later, once the Roman Catholic Church was established, the church tried to do away with the pagan holiday of Samhain and replace it with the religious holiday of “All Saint’s Day” on Nov. 1. The tradition of All Hallow’s Eve however still lasted and leads to what is known today as “Halloween.”

During the early colonization of America, many settlers brought the traditions of Halloween with them. The early Puritan Church, however, did not agree with the celebration of this holiday, and therefore the popularity of the holiday was scarce. During this time though, many of the legends of the Native Americans and early colonists combined, and it is believed this is where we get many of our traditions such as witches and other superstitions associated with Halloween.

Finally, the modern tradition of Halloween became popular after the influx of immigrants from the Irish famine. And finally in the 1920s, the cultural tradition of Halloween, as we know it today, became the norm. In the 50s, Halloween exploded into a multi-million dollar holiday to the pleasure of adults and kids alike.