Samhain, (All Hallows Eve, Halloween) originated with the Celtic tribes who lived in Ireland, Scotland, Wales and Brittany. For the Celts this Festival marked the end of summer - the coming of winter. the two halves of the year - the dark and the light. Summer runs from Beltane to Samhain and winter from Samhain to Beltane. Samhain is one of the Greater Sabbats observed by pagans and Wiccans.
For Celts Samhain is a time when the bridge that separates the world of the living and the world of the dead becomes firmer, allowing spirits and ghosts and ghouls to cross over. These spirits or departed souls are honored and asked to grant luck and prosperity. Regardless what you call it today it is a festival dedicated to the dead
As the souls of the dead walk the land so do the evil spirits, people wear masks and light bonfires to scare them away.