Short answer: Halloween started as an ancient Celtic festival, called Samhain, where people would wear costumes to scare off dead spirits and ghosts.
Samhain marked the end of the summer harvest and ushered in the colder months. Celts believed that the boundaries between the living and the dead would blur during this time. People traditionally wore costumes in hopes they could ward off these dead spirits. Poorer people would visit the houses of wealthier families and promise to pray for the souls’ of previous house owners that had passed away in exchange for pastries (called soul cakes).
In Scotland and Ireland, children went from house to house singing songs and doing tricks in exchange for food, money, etc. This is the origin of the modern day “trick or treat.”
By 43 AD, the Roman Empire had conquered most of the Celtic territory. They combined two of their festivals with Celtic festivals.
The second festival was called Pomona. Pomona was the Roman goddess of fruit and trees, and the symbol of Pomona was the apple. Most historians believe this explains our Halloween tradition of “bobbing for apples.”
In 609 AD, Pope Gregory III added the custom of praying for the dead to the festival. November 1st was designated as the time to honor saints and martyrs. This was known as All Saints Day. All Saints Day became known as All Hallows (from Middle English word, Alholowmesse, meaning All Saints’ Day). The day before All Hallows people continued to celebrate the Celtic tradition of Samhain. This became known as Hallows Eve. Hallows Eve eventually became Hallows Evening. Hallows Evening eventually became Halloween.
Over time, Halloween became a night where children wear costumes and “trick or treat” for candy.
What candy do you like getting on Halloween?