Trick-or-treating is a recent 20th century American phenomenon, but it has roots in ancient customs. The Irish originally initiated a custom hundreds of years ago where groups of farmers would go house to house soliciting food for the village. Prosperity was promised for generous givers and threats were made against the stingy villagers.
The custom of trick-or-treating is also related to the Gaelic practice of giving cakes to the poor at Samhain or ?summer-end,? a seasonal festival that coincided with All Souls Day. They came to be called ?soul-cakes,? and in return recipients were obligated to pray for a good harvest.