Most scholars agree that Halloween originated around 2,000 years ago, when pagan Celtic people in Europe celebrated the end of the harvest and the start of a new year in a festival called Samhain, which was held on November 1 in contemporary calendars. It was believed that on that day, the souls of the dead returned to their homes, so people dressed in costumes and lit bonfires to ward off spirits.

Early Christianity adopted many pagan holidays and traditions, therefore Halloween is also thought to have influences from Christian beliefs and practices. The English word 'Halloween' comes from "All Hallows' Eve", being the evening before the Christian holy days of All Hallows' Day (All Saints' Day) on 1 November and All Souls' Day on 2 November.