About

Samhain (sɑːwɪn) or Sauin  is a Gaelic festival on 1 November marking the end of the harvest season in autumn and beginning of winter or the darker half of the year. It is also the Irish and Scottish Gaelic name for November. Celebrations begin on the evening of 31 October, since the Celtic day began and ended at sunset. This is about halfway between the autumnal equinox and winter solstice. It is one of the four Gaelic seasonal festivals along with Imbolc, Bealtaine, and Lughnasa. Historically it originated in Ireland and it was widely observed throughout Ireland, Scotland, and the Isle of Man. 
Samhain is believed to have Celtic pagan origins, and some Neolithic passage tombs in Ireland are aligned with the sunrise at the time of Samhain. Samhain is mentioned in the earliest Irish literature, from the 9th century, and is associated with many important events in Irish mythology. The early literature says Samhain was marked by great gatherings and feasts and was when the ancient burial mounds were open, which were seen as portals to the Otherworld. Some of the medieval tales also associate Samhain with bonfires and sacrifice.

In the 9th century, the Western Church endorsed 1 November as the date of All Saints’ Day, possibly due to the influence of Alcuin or Irish missionaries, and 2 November later became All Souls’ Day. It is believed that Samhain and All Saints’/All Souls’ influenced each other and the modern Halloween.Most American Halloween traditions were inherited from Irish and Scottish immigrants. Folklorists have used the name ‘Samhain’ to refer to Gaelic ‘Halloween’ customs until the 19th century.

Since the later 20th century Celtic neopagans and Wiccans have observed Samhain, or something based on it, as a religious holiday.