Modern-day Halloween festivities are a result of hybridization of Celtic, Catholic, and English traditions. The Celts, who lived two thousand years ago in what is now Britain, France, and northern Spain, celebrated the festival of Samhain in late October. Samhain marked the beginning of winter-a time commonly associated with death-and was believed to be a time when the boundary between the world of the dead and the world of the living could easily be crossed. People wore masks and disguises so that they wouldn't be recognized by evil spirits who had come to visit the earth. Turnips, rutabagas, or large beets were carved to look like faces; and as with all Celtic festivals, Samhain was celebrated with bonfires.
Later, after the Celtic territories had come under the influence of Catholicism, Pope Gregory IV saw fit to Christianize the Celts and sought to eradicate their "pagan" holidays by replacing them with Christian ones. Thus in the ninth century All Saints' Day was moved from 13 May to 1 November, and the festival of Samhain and the Catholic day for the dead were made one. The new celebration became known as All-hallow's day, or the day of all saints. The night before became known as All-Hallow's Eve.
As European immigrants came to America, they brought their Halloween traditions with them. Naturally, the "pagan" holiday of Halloween did not flourish in Puritan New England; Halloween festivities were much more widespread in Virginia and in the mid-Atlantic colonies. It wasn't until the late 1840s, however, that Halloween really became popular in America. During this time, Irish immigrants were pouring into the United States by the tens of thousands as a result of the Great Potato Famine. Inheritors of the Celtic traditions, the Irish celebrated Halloween as it had been celebrated in Ireland for centuries. Instead of carving jack o' lanterns out of root vegetables, however, as was traditional in old Ireland, they were carved out of pumpkins, which were more readily available in America.
English traditions have also influenced the way Halloween is celebrated today; the practice of trick-or-treating can be traced back to All Saints' Day parades, when the poor went from door to door begging food (usually a "soul cake") for their families, and in exchange promised to pray for the dead relatives of those giving them food. Later children began dressing in costume and going from door to door asking for food or money.
Halloween is primarily celebrated in places with Celtic roots, and is not popular worldwide. However, El Día de los Muertos is widely celebrated in Catholic countries. Unlike Halloween, which is now nothing more than a secular holiday, the Day of the Dead has not lost its original religious meaning. On El Día de los Muertos, people burn candles and leave food and flowers for their dead relatives.
Evidently the legacy of the Celts-and the early Catholics-lives on.