Samhain marked the Celtic New Year, the end of summer, and the end of the harvest season. It also signaled the beginning of winter, which they associated with death. On this day, the Celts believed the veil between the living and the dead was especially thin. This allowed spirits of the dead to visit the living.

Yet, the Halloween holiday has its roots in the ancient Celtic festival of Samhain (a Gaelic word pronounced “SAH-win”), a pagan religious celebration to welcome the harvest at the end of summer, when people would light bonfires and wear costumes to ward off ghosts.

According to the later Dindsenchas and the Annals of the Four Masters—which were written by Christian monks—Samhain in ancient Ireland was associated with a god or idol called Crom Cruach. The texts claim that a firstborn child would be sacrificed at the stone idol of Crom Cruach in Magh Slécht.

Halloween (Samhain) is not an evil celebration. Samhain is about honouring ancestors and dearly departed, the season, and warding off evil. It's about light overcoming dark. And, in this way you can see how Samhain shares similarities with other festivals taking place around the world at this time of year.