Over the years, Oct. 31 has been associated with frightening sights and wacky costumes,like the ones readers have submitted here, but the sugar-fueled holiday we know and love has a pretty complicated heritage that goes back more than two millennia.

The earliest roots of Halloween can be traced back to the ancient Celtic festival of Samhain. The Celts, who inhabited the British Isles and some of France, celebrated their new year on Nov. 1, and they believed that on the day before, the dead could cross into the living world. To guide the souls back home and prevent them from causing trouble, the Celts would light bonfires, leave out food and drink and dress up like the spirits they were trying to ward off.

By 43 AD, the Romans conquered most of the Celtic lands and combined Samhain with two Roman festivals. Feralia was held to honor the dead, and the festival of Pomona, the Roman goddess of fruit and trees, was also celebrated around the same time. As Christianity expanded, those festivals to honor deities and the dead were moved to the beginning of November, and the day before All Saints’ Day (or All Hallows) was also celebrated as a day for the evil spirits that had returned. Eventually, All Hallows’ Eve on Oct. 31 became Halloween.

Halloween as we know it came to the United States from the traditions of Irish and British immigrants in the 1800s. After the church shifted away from leaving treats for the roaming spirits and replaced it with leaving soul cakes in exchange for prayers for the dead, children would go door to door to gather the food. They would often dress up as the spirits in question and perform songs or skits. As communities shied away from the supernatural and religious undertones, Halloween eventually became the festival of costume parties and warding off potential tricksters with small treats.

a.hutchinson@theday.com

Twitter: @ahutch411