How did I not know Halloween had such Celtic roots? Have I just not been paying attention?
Halloween has origins in the ancient Celtic festival known as Samhain[pronounced: sow- wen] (Irish pronunciation: [ˈsˠaunʲ]; from the Old Irish samhain, possibly derived from Gaulish samonios). The festival of Samhain is a celebration of the end of the harvest season in Gaelic culture, and is sometimes regarded as the "Celtic New Year". Traditionally, the festivalwas a time used by the ancient Celtic pagans to take stock of supplies and slaughter livestock for winter stores. The ancient Celts believed that on October 31st, now known as Halloween, the boundary between the living and the deceased dissolved, and the dead become dangerous for the living by causing problems such as sickness or damaged crops. The festivals would frequently involve bonfires, into which the bones of slaughtered livestock were thrown. Costumes and masks being worn at Halloween goes back to the Celtic traditions of attempting to copy the evil spirits or placate them, inScotland for instance where the dead were impersonated by young men with masked, veiled or blackened faces, dressed in white.