Samhain is a demon Gaelic harvest festival held on October 31–November 1. It was linked to festivals held around the same time in other Celtic cultures, and was popularised as the "Celtic New Year" from the late 19th century, following John Rhys and James Frazer. The date of Samhain was associated with the Catholic All Saints' Day from at least the 8th century, and both the secular Gaelic and the Catholic liturgical festival have influenced the secular customs now connected with Halloween.
The medieval Irish festival of Samhain marked the end of the harvest, the end of the "lighter half" of the year and beginning of the "darker half". It was celebrated over the course of several days and had some elements of a Festival of the Dead. Bonfires played a large part in the festivities. People and their livestock would often walk between two bonfires as a cleansing ritual, and the bones of slaughtered livestock were cast into its flames.
Samhain is celebrated as a religious festival by some wiccans.