Halloween is the common name of All Saints' Day, which is originally a religious festival of Catholicism and other Christian religions. The time is November 1st. The Catholic Church designates All Saints' Day as a mass day. On this day, unless there are irresistible reasons, all believers must go to the church to attend mass to remember all the saints who have passed away and ascended to heaven, especially those in Catholic history. Famous saint. One theory is: Legend has it that since 500 BC, the Celts (CELTS) living in Ireland, Scotland and other places moved this festival forward by one day, to October 31. They believe that this day is the official end of summer, the beginning of the new year and the beginning of the harsh winter. At that time, people believed that the souls of their deceased friends would return to their former homes on this day to find souls in living people so as to be reborn. This was the only hope for rebirth after death. The living people are afraid of the souls of the dead coming to seize their lives, so people put out furnace fires and candlelights on this day so that the souls of the dead cannot find living people. They also dress up as monsters and monsters to scare away the souls of the dead. After that, they will rekindle the fire and candlelight and start their life in the new year. Another theory is that the Druids, the priests of ancient Gaul, Britain and Ireland, had a grand festival to praise autumn, which lasted for a whole day from midnight on October 31st to November 1st the next day. They believe that on that night, their great god of death, Saman, summoned all the ghosts of those who died that year, and these evil ghosts would be punished by being reborn as animals. Of course, just the thought of such a spooky gathering was enough to frighten the simple-minded ignorant people at that time. So they lit a bonfire that reached into the sky and closely monitored these evil spirits. This is how the idea that witches and ghosts were everywhere on Halloween began. To this day, in some isolated areas of Europe, some people still believe this to be true. Another thing is: the ancient Romans also had a festival on November 1st, which was used to pay respect to their goddess Pomona. They roasted nuts and apples in front of a roaring fire. Today's Halloween seems to be a combination of ancient Roman festivals and Druid festivals.