I do not know where others get their information about Halloween, but I have done research on the Celtic (pronounced "keltik") origin of what is now known as Halloween.
For the ancient Celts (pronounced "kelts"), the night of Halloween was
not a night for celebration. Instead, it was just the opposite.
The Celts believed that on that night, demons were allowed to roam on the Earth. The goal of the Celts was to
avoid those demons, possibly shooing them away. The druids had the task of using their religious rituals to try to
drive away the demons.
Commoners, meanwhile, hid in their homes. If any person needed to go outside, then that person donned a disguise in an attempt to trick the demons into believing that the person was a demon, too, so that the demons would not harass or harm the person.
Again, the Celts wanted to be protected from demons. Worshiping demons was unthinkable.
Thankfully, Celtic Christian missionaries ( such as
Columba) spread the news that there were no demons roaming the Earth on that night. The missionaries explained to the Celts how the God of Christianity ruled Heaven and Earth and how Christ Jesus had defeated Satan, the leader of demons.
Knowing that Satan had been conquered enabled the Celts to stop living in fear on the night of October 31st. They no longer had need for the druids, and so druids became relics. The Celts gladly converted to the Christian faith.
Today, Halloween is a time for fun only, for pretending to be someone else for a short while. Participants understand that there are no demons roaming the Earth on that night.
Sadly, Halloween has been hijacked by people who participate in Wicca and Satanism. They turned October 31st into something that it was not originally.
If some people are opposed to the non-religious modern-day Halloween tradition, then so be it. That doesn't bother me.
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Personal Note: I learned about the ancient Celts because the were my ancestors, as were the Picts, also.