For adults and children both, October 31 is one of the most anticipated days on the calendar. It marks a day of mischief, creativity and candy, but why do we celebrate Halloween at all?

About 2,000 years ago, as weather in what is now Ireland, the United Kingdom and Northern France, transitioned from the bounty of summer into the deep freeze of winter, the native Celtic peoples celebrated the night before their New Year, Nov. 1. They called it Samhain (pronounced “sow-in”), and on this day, Oct. 31, they believed the boundaries between the world of the living and that of the dead blurred and the spirits roamed the land of the living for one night.

These unleashed spirits caused mischief, damaged the last of the summer’s coveted crops … and allowed the Celtic Druids, upheld as priests, to peer into the future. The Druids gathered around massive, sacred bonfires wearing intricate costumes made of animal heads and skins to tell each other’s fortunes.

The Celtic lands were mostly conquered by the Romans, who incorporated traditional Roman festivals into Samhain. Later, on May 13, 609 A.D., Pope Boniface IV established All Saints Day, which was later broadened to celebrate all martyrs as well and moved to Nov. 1.

As Christianity spread into Celtic lands, the church supplanted the Pagan Samhain with All Souls’ Day, Nov. 2, to honor the dead. All Souls Day maintained many of the traditions of Samhain, including large bonfires, parades and costumes in the form of saints, angels and devils.

The All Saints Day celebration was also referred to as All-Hollows or All-Hallowmas, and the night before it, Oct. 31, All-Hallows Eve. Now, we call the day Halloween and celebrate with elaborate costumes, family-friendly activities like trick-or-treating and, for the young adults, a little debauchery.

Halloween costumes