Samhain, a Celtic festival dating back over 3,000 years, is considered one of the roots of Halloween. During Samhain, the Celts celebrated the end of summer and the beginning of winter, believing that on this night the boundary between the world of the living and the dead narrowed, allowing good and evil spirits to cross between both worlds.

Over time, the Christian Church established All Saints' Day on November 1st, and the eve of this feast became Halloween, or All Hallows' Eve.