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. It begins the observance of Allhallowtide, the time in the liturgical year dedicated to remembering the dead, including saints, martyrs, and all the departed. One theory holds that many Halloween traditions were influenced by Celtic harvest festivals, particularly the Gaelic festival Samhain, which are believed to have pagan roots; some go further and suggest that Samhain may have been Christianized as All Hallow's Day, along with its eve, by the early Church. Other academics believe Halloween began solely as a Christian holiday, being the vigil of All Hallow's Day. Celebrated in Ireland and Scotland for centuries, Irish and Scottish migrants brought many Halloween customs to North America in the 19th century, and then through American influence, Halloween spread to other countries by the late 20th and early 21st century. Halloween activities include trick-or-treating , 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. 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. 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. Halloween is thought to have roots in Christian beliefs and practices.The name 'Halloween' comes from "All Hallows' Eve", being the evening before the Christian holy days of All Hallows' Day (All Saints' Day) on 1 November and All Souls' Day on 2 November. Since the time of the early Church, major feasts in Christianity (such as Christmas, Easter and Pentecost) had vigils that began the night before, as did the feast of All Hallows'. These three days are collectively called Allhallowtide and are a time for honoring the saints and praying for recently-departed souls who have yet to reach Heaven. Commemorations of all saints and martyrs were held by several churches on various dates, mostly in springtime. It was held on 13 May in 4th century Roman Edessa, and on 13 May 609, Pope Boniface IV re-dedicated the Pantheon in Rome to "St Mary and all martyrs". This was the date of Lemuria, an ancient Roman festival of the dead. Beginning in the 4th century, the feast of All Hallows' in the Western Christian Church commemorated Christian martyrs and in the 8th century, Pope Gregory III (731–741) founded of an oratory in St Peter's for the relics "of the holy apostles and of all saints, martyrs and confessors". Some sources say it was dedicated on 1 November, while others say it was on Palm Sunday. By 800, there is evidence that churches in Ireland and Northumbria were holding a feast commemorating all saints on 1 November. Alcuin of Northumbria, a member of Charlemagne's court, may then have introduced this 1 November date in the Frankish Empire. In 835, it became the official date in the Frankish Empire.