Maybe you’re planning to go to a Halloween party soon, or you’re looking forward to trick-or-treating. Your preparations for Halloween will be different than those of the Celts in Ireland 2,000 years ago, but their festival of Samhain (pronounced sow-in), was the first celebration of the holiday. Samhain represented the Celtic new year—the time when summer ended and winter began. The word Samhain means the end of summer. During this period, the ghosts of the dead returned to visit the living. In order to prevent the dead from causing havoc and perhaps destroying crops, the Celts wore animal costumes and masks. The Celts also left out gifts of food for the spirits and burnt crops and animals to appease the Celtic gods.

When the Romans conquered Celtic territory, a blend of Celtic and Roman traditions for honoring the dead occurred. In 1000 A.D., the Catholic church made November 2 All Souls’ Day, celebrated much like Samhain with bonfires and people dressed in costumes as saints, angels, and devils. November 1 (All Saints’ Day) was set aside to honor only saints and martyrs, but the evening before it, when the Celts had celebrated Samhain, was called All-hallows Eve. Thus the original date the Celts celebrated Samhain became our present day Halloween.

Children did not come to the doors of people’s homes shouting trick-or-treat during these early Halloween celebrations, however. One possible precedent for trick-or-treating started in medieval Europe on All Souls’ Day. An English version depicted beggars and children asking people for soul cakes, which when eaten would help a lost soul get to heaven.  Halloween reached the U.S. thanks to Irish immigrants who came to the country in the nineteenth-century, but the focus of the day was more on parties and pranks than candy. Tricks played by children included covering windows with soap, removing gates, and tying doors shut. Adults in small towns who usually knew the neighborhood kids went along with the story that the tricks were performed by goblins and witches.

As American towns grew into cities where people no longer knew one another, adults got tired of the pranks. Communities started holding costume parties to get control over what the kids did on Halloween. By the 1930s, homeowners offered treats to children on Halloween if they promised not to play any tricks. Today kids attend parties and yell “trick or treat” at the doors of neighbors, though many don’t know how these traditions got started. So if you want to play a harmless trick on your friends this Halloween, see if they can guess the history behind Halloween.

For more on the history of Halloween, see http://www.history.com/topics/halloween