Jack Santino, a folklorist, writes that 'there was throughout Ireland an uneasy truce existing between customs and beliefs associated with Christianity and those associated with religions that were Irish before Christianity arrived'. Today's Halloween customs are thought to have been influenced by folk customs and beliefs from the Celtic-speaking countries, some of which are believed to have pagan roots. ДЄn early 20th-century Irish Halloween mask displayed at the Museum of Country Life Some Christians historically abstained from meat on All Hallows' Eve, a tradition reflected in the eating of certain vegetarian foods on this vigil day, including apples, potato pancakes, and soul cakes. For some people, the Christian religious observances of All Hallows' Eve, including attending church services and lighting candles on the graves of the dead, remain popular, although for others it is a secular celebration. Halloween activities include trick-or-treating (or the related guising and souling), attending Halloween costume parties, carving pumpkins into jack-o'-lanterns, lighting bonfires, apple bobbing, divination games, playing pranks, visiting haunted attractions, telling scary stories, as well as watching horror films. Other academics believe, however, that Halloween began solely as a Christian holiday, being the vigil of All Hallow's Day.

One theory holds that many Halloween traditions may have been influenced by ancient Celtic harvest festivals, particularly the Gaelic festival Samhain, which may have had pagan roots some scholars hold that Samhain may have been Christianized as All Hallow's Day, along with its eve, by the early Church. It begins the observance of Allhallowtide, the time in the liturgical year dedicated to remembering the dead, including saints (hallows), martyrs, and all the faithful departed. Halloween or Hallowe'en (a contraction of 'All Hallows' evening'), also known as Allhalloween, All Hallows' Eve, or All Saints' Eve, is a celebration observed in many countries on 31 October, the eve of the Western Christian feast of All Hallows' Day. Totensonntag, Blue Christmas, Thursday of the Dead, Samhain, Hop-tu-Naa, Calan Gaeaf, Allantide, Day of the Dead, Reformation Day, All Saints' Day, Mischief Night ( cf. Trick-or-treating, costume parties, making jack-o'-lanterns, lighting bonfires, divination, apple bobbing, visiting haunted attractions.Д¬hurch services, prayer, fasting, and vigil Western Christians and many non-Christians around the world

On this day may 9