Halloween is an Irish holiday. It's true. About 2,000 years ago, Celts celebrated Samhain on October 31st and this Samhain festival eventually evolved into what we know as Halloween.
The Celtic festival of Samhain took place on October 31st because the Celts celebrated their new year on November 1st, a day that marked the end of summer. Winter was a time associated with death so the whacky Celts believed ghosts of the dead returned to earth on the night before. When Christianity permeated Irish society in the 800s, Samhain evolved into All Saints' Day which translated into All Hallows. The evening was naturally referred to as All Hallows Eve and after a few pints of Guiness All Hallows Eve sounds an awful lot like Halloween.
