Why Do We Celebrate Halloween?

Ever wonder why we dress up in costumes and go door-to-door for candy? The answer goes back thousands of years.

Our own summary of the original — the full post and photos live at britannica.com.

Halloween traces its roots to the ancient Celtic festival of Samhain, when people lit bonfires and wore costumes to ward off ghosts. Later, Pope Gregory III designated November 1 as All Saints' Day, and the night before became known as All Hallows' Eve, eventually Halloween. Irish immigrants brought the tradition to America in the 19th century.

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A Britannica explainer on the origins and evolution of Halloween. It traces the holiday from the ancient Celtic festival of Samhain through the Christian creation of All Saints' Day and All Hallows' Eve, and on to the modern secular celebration of costumes, jack-o'-lanterns, and trick-or-treating. The page mixes a narrative history of the holiday with a short companion article on how October 31 came to be celebrated worldwide.

Facts from the original

Parts of Halloween may have been around for more than a thousand years.

Halloween began as serious religious observances and became increasingly secular over the centuries, with the religious trappings all but disappearing.

Today Halloween is a holiday of spooky fun characterized by jack-o'-lanterns on porches and children going door to door for treats.

Some of Halloween's roots are thought to stretch back to the ancient Celtic festival of Samhain, observed in Ireland on November 1.

On Samhain it was believed that the boundaries between the living and the dead, and between humans and gods, grew thin and supernatural episodes abounded.

The occasion may have been considered fraught with danger, and people may have dressed in costumes and possibly lit bonfires to ward off wandering spirits and malevolent acts.

Those mystical rituals may have helped give modern Halloween its cast of classic characters—witches, ghosts, goblins, and other things that go bump in the night—and the lighthearted practice of dressing up.

The ancient Celts believed that on November 1 the souls of those who had died returned to visit their homes or to journey to the otherworld.

People set fires to frighten away evil spirits, and they sometimes wore masks and other disguises to avoid being recognized by ghosts.

In the 7th century CE, Pope Boniface IV created All Saints Day as a holy day on May 13.

A century later, Pope Gregory III moved the holiday to November 1, likely as a Christian substitute for the pagan festival.

The evening before the saintly celebration became known as All Hallows' Eve, which was eventually shortened to Halloween.

In the 8th century the Roman Catholic Church moved All Saints' Day to November 1, perhaps in an effort to end the pagan holiday.

Christian traditions appear to have blended with remnants of Samhain customs, and Halloween eventually spread to other parts of the world.

The early Puritan colonists in New England did not celebrate Halloween, but the holiday did enjoy some popularity in the Southern colonies.

By the 1800s, fall harvest festivals borrowed many Halloween elements.

Irish immigrants escaping the Great Potato Famine brought along many more customs that remain today, such as jack-o'-lanterns.

Trick-or-treating, in which children dress up in costume and ask for treats from neighbors, took shape in the early 1900s.

Trick-or-treating grew out of an old Irish and Scottish custom called "guising," in which a person would dress up, tell a joke, recite a poem, or perform some other little trick, and get a treat in return.

By mid-century trick-or-treating had evolved into the familiar candy-fueled door-to-door ritual.

Trick-or-treating now fuels billions of dollars in candy sales in the United States every year.

While the day was celebrated by some Christians, many Samhain traditions persisted, and Halloween eventually became more commonly known as a secular holiday.

On October 31 people around the world celebrate All Hallows' Eve.

From the original

Halloween's roots are thought to reach back more than a thousand years to Samhain, an ancient Celtic festival observed in Ireland on November 1 and considered one of the most sinister dates on the Celtic calendar. The Celts believed that on that day the boundary between the living and the dead, and between humans and gods, grew thin, and that the souls of the dead returned to visit their homes or travel to the otherworld. People may have worn costumes and disguises to avoid being recognized by ghosts, and lit bonfires to frighten off wandering spirits and malevolent forces. Those practices are thought to have supplied modern Halloween with its classic cast of witches, ghosts, and goblins. Centuries later the Christian church layered its own traditions onto the date: in the 7th century CE Pope Boniface IV made All Saints Day a holy day on May 13, and a century later Pope Gregory III moved it to November 1, likely as a Christian substitute for the pagan festival. The evening before became All Hallows' Eve, later shortened to Halloween. Samhain customs persisted and blended with Christian practice, and the holiday spread. Puritan colonists in New England ignored it, though it found some popularity in the Southern colonies; by the 1800s fall harvest festivals borrowed many Halloween elements, and Irish immigrants fleeing the Great Potato Famine carried over customs such as jack-o'-lanterns. Trick-or-treating emerged in the early 1900s from the Irish and Scottish custom of "guising," and by mid-century had become the candy-fueled door-to-door ritual celebrated today.