The modern-day incarnation of Halloween may feed on candy corn and mass-produced costumes, but it was born out of ancient Celtic traditions.

The Celts lived 2,000 years ago in what is now the United Kingdom, Ireland and northern France. Before Christianity took hold, these pagan people marked the end of summer — and their recorded year — with the festival of Samhain on Oct. 31, according to the History Channel’s Web site.

They believed that on that night, the souls of the dead returned to earth. The Celts blamed the ghosts for wreaking havoc while here but also thought their presence made it easier for Druid priests to foretell the future.

Donning costumes fashioned from animal skins and heads so as not to be recognized by the ghosts, they built fires to sacrifice animals and burn crops as offerings to Celtic deities in anticipation of the coming winter and to pacify the spectres.

Samhain ultimately morphed into All-hallows Eve and what we now call Halloween following the Roman conquest.

The American tradition of "trick-or-treating" probably dates back to the early All Souls’ Day parades in England when the poor would beg for "soul cakes" in return for prayers on behalf of the dead, according to the History Channel.

Going "a souling" was encouraged by the church as a means of replacing the pagan practice of leaving goodies for the roaming spirits and was eventually taken up by children.

So while Halloween is decidedly commercial and secular for most who dress up and go trick-or-treating, it’s no Hallmark holiday.