@ReneBumsWombats This is from BibleInfo.com:
'The origin of Halloween as we know it, began over 1900 years ago in England, Ireland, and Northern France. It was a Celtic celebration of the new year, called Samhain which occurred on November 1. The Celtic druids revered it as the biggest holiday of the year and emphasized that day as the time when the souls of the dead supposedly could mingle with the living. Bonfires were a large aspect of this holiday as well.
Samhain remained popular until St. Patrick and other Christian missionaries arrived in the area. As the population began to convert to Christianity the holiday began to lose its popularity. However, instead of eradicating pagan practices such as “Halloween” or Samhain, the church used these holidays with a Christian twist to bring paganism and Christianity together, making it easier for local populations to convert to the state religion.
Another tradition is the druidic belief that during the night of November 1, demons, witches, and evil spirits freely roamed the earth with joy to greet the arrival of “their season”—the long nights and early dark of the winter months. The demons had their fun with poor mortals that night, frightening, harming, and even playing all kinds of mean tricks on them. The only way, it seemed, for scared humans to escape the persecution of the demons was to offer them things they liked, especially fancy foods and sweets. Or, in order to escape the fury of these horrible creatures, a human could disguise himself as one of them and join in their roaming. In this way, they would recognize the human as a demon or witch and the human would not be bothered that night.
During the time of the Roman empire, there was the custom of eating or giving away fruit, especially apples, on Halloween. It spread to neighboring countries; to Ireland and Scotland from Britain, and to the Slavic countries from Austria. It is probably based upon a celebration of the Roman goddess Pomona, to whom gardens and orchards were dedicated. Since the annual Feast of Pomona was held on November 1, the relics of that observance became part of our modern-day Halloween celebrations, for instance, the familiar tradition of “dunking” for apples.
Today costumes take the place of disguises and candy has replaced fruits and other fancy foods as children go door-to-door trick-or-treating. Originally trick-or-treating began as “souling,” when children would go door-to-door on Halloween, with soul cakes, singing and saying prayers for the dead. Over the course of history Halloween’s visible practices have morphed and merged with the culture of the day, but the purpose of honoring the dead, veiled in fun and festivities, has remained the same.'
As another poster said, the church incorporated pagan festivals rather than appropriating them.