Halloween is very popular in Ireland, where it is believed to have originated, and is known in Irish as OĆche Shamhna, literally "Samhain Night". Pre-Christian Celts had an autumn festival, Samhain (pronounced /sow-in/ from the Old Irish samain), "End of Summer", a pastoral and agricultural "fire festival" or feast, when the dead revisited the mortal world, and large communal bonfires would hence be lit to ward off evil spirits.
Pope Gregory IV standardized the date of All Saints' Day, or All Hallows' Day, on November 1 in the name of the entire Western Church in 835. As it now began at sunset, the holiday coincided exactly with Samhain. It is claimed that the choice of date seems consistent with the common practice of leaving pagan festivals and buildings intact (e.g., the Pantheon), while overlaying a Christian meaning. However, there is no actual documentation of any reliability, whatsoever, backing up the presumption. While the Celts might have been content to move All Saints' Day from their own previous date of April 20, the rest of the world celebrating it on May 13, it is speculated without evidence that they were unwilling to give up their pre-existing autumn festival of the dead and continued to celebrate Samhain.
Unfortunately, there is frustratingly little primary documentation of how Halloween was celebrated in preindustrial Ireland. Historian Nicholas Rogers has written, "It is not always easy to track the development of Halloween in Ireland and Scotland from the mid-seventeenth century, largely because one has to trace ritual practices from [modern] folkloric evidence that do not necessarily reflect how the holiday might have changed; these rituals may not be "authentic" or "timeless" examples of pre-industrial times."
On Halloween night in present-day Ireland, adults and children dress up as creatures from the underworld (e.g., ghosts, ghouls, zombies, witches and goblins), light bonfires, and enjoy spectacular fireworks displays, despite the fact that such displays are usually illegal. It is also common for fireworks to be set off for the entire month preceeding Halloween, as well as a few days after. Halloween was perceived as the night during which the division between the world of the living and the otherworld was blurred so spirits of the dead and inhabitants from the underworld were able to walk free on the earth. It was believed necessary to dress as a spirit or otherworldly creature when venturing outdoors to blend in, and this is where dressing in such a manner for Halloween comes from. This gradually evolved into trick-or-treating because children would knock on their neighbours' doors, in order to gather fruit, nuts, and sweets for the Halloween festival. Salt was once sprinkled in the hair of the children to protect against evil spirits.
The houses are frequently adorned with pumpkins or turnips carved into scary faces; lights or candles are sometimes placed inside the carvings to provide an eerie effect. The traditional Halloween cake in Ireland is the barmbrack, which is a fruit bread. Barmbrack is the centre of an Irish Halloween custom. The Halloween Brack traditionally contained various objects baked into the bread and was used as a sort of fortune-telling game. In the barmbrack were: a pea, a stick, a piece of cloth, a small coin (originally a silver sixpence) and a ring. Each item, when received in the slice, was supposed to carry a meaning to the person concerned: the pea, the person would not marry that year; the stick, "to beat one's wife with", would have an unhappy marriage or continually be in disputes; the cloth or rag, would have bad luck or be poor; the coin, would enjoy good fortune or be rich; and the ring, would be married within the year. Commercially produced barmbracks for the Halloween market still include a toy ring.
Games are often played, such as bobbing for apples, where apples, peanuts and other nuts and fruit and some small coins are placed in a basin of water. The apples and nuts float, but the coins, which sink, are harder to catch. Everyone takes turns catching as many items possible using only their mouths. In some households, the coins are embedded in the fruit for the children to "earn" as they catch each apple. The Scottish and English have adapted the tradition to a game named "ducking", in which a participant quickly dunks in a water-filled container in an attempt to get a prize, without being submerged too long. Another common game involves the hands-free eating of an apple hung on a string attached to the ceiling. Games of divination are also played at Halloween, but are becoming less popular.
At lunch-time (midday meal, known as "dinner" in Ireland), a traditional Halloween meal Colcannon is eaten, often with coins wrapped in grease-proof paper mixed in. In recent decades the practice of midday dinners in the home has declined and with it this traditional Halloween ritual. Irish children have a week-long Halloween break from school; the last Monday in October is a public holiday given for Halloween even though they often do not fall on the same day.