The word itself "Halloween" was originally called "All Hallows Eve", which means the evening before All Saints Day. "All Hallow Day" or "All Saints Day, is a Catholic day of observance in honor of Saints.
But in the 5th century , in Celtic Ireland, summer officially ended on October 31. The holiday was called Smhai. the Celtic New Year. One story says on that day the disembodied spirits of all those who had died throughout the preceding year would come back in search of living bodies to possess for the next year. It was believed to be their only hope for the afterlife. The celts believed all laws of space and time were suspended during this time allowing the spirit world to intermingle with the living.
Naturally the still-living did not want to be posessed. So on the night of October 31 villagers would extinguish the fires of their homes, to make them cold and undesirable. They would then dress up in all manner of ghoulish costumes and noisily paraded around the neighborhood, being as destructive as possible in order to frighten away spirits looking for bodies to posess. The Custom of Halloween was brought to America in the 1840's by Irish immigrants fleeing their country's potato famine. The custom trick-or-treating is thought to have originated not with the Irish celts, but with a ninth-century European custom called souling. On November2, all souls Day, early Christians would walk from village to village begging for "soul cakes" made out of square pieces of bread with currants.
The more soul cakes the beggars would receive the more prayers they would promise to say on behalf of the dead relatives of the donors.
