Find out the origin and meaning behind jack-o’-lanterns, trick-or-treating, costumes and other Halloween traditions.

Folklorists created a through line from the Celtic pagan festival of Samhain to Halloween. But the Halloween we know today has more to do with the English, a 9th century pope and American consumerism.

The origin of Halloween is often attributed to the ancient Celtic celebration of Samhain (pronounced “sow-in”), which marked the end of summer and its harvest and the beginning of winter.

(The Conversation is an independent and nonprofit source of news, analysis and commentary from academic experts.) The Irish often get credit – or blame – for the bonfires, pranksters, witches ...