“Trick or treat!” is arguably one of the most well known phrases in modern American society. When someone says these three words, they are usually asking for candy October 31, a.k.a Halloween. Trick-or-treating is a common practice that many US children participate in. But when did this tradition of dressing in costumes and asking for treats start?

According to history.com, Halloween has its roots in the ancient, pre-Christian Celtic festival of Samhain which was celebrated October 31. The Celts believed that the dead returned to earth that day and would offer sacrifices and light bonfires to pay their respects.

During these celebrations, the Celts would dress up in animal fur costumes to scare away unwelcome spirits and visitors. Leftover food was set out at night as another way to deter unwanted spirits.

As Christianity spread through predominantly Celtic areas, the church adopted Celtic rituals that influenced the creation of All Soul’s Day November 2, a day to honor the dead. During All Soul’s Day, poor children would practice “souling” where they would visit wealthier families to receive treats and gifts in exchange for prayers towards dead family members.

Children in Scotland also participated in a similar tradition called “guising” where they would dress up and do a “trick” like dancing or recite a poem to earn some sort of treat.

Immigrants escaping the potato famine in the 1800’s helped revive the traditions of Halloween. Irish and Scottish communities continued “souling” and “guising” practices which eventually spread throughout the United States.

As The Great Depression worsened, Halloween became an excuse for mischief and trickery in suburban communities. During WWII, the supply of treats for Halloween diminished and left many children without treats for the holiday. But after the post-war baby boom, trick-or-treating increased in popularity and became a standard American practice to what we know today.

The phrase “trick-or-treat” has no definite origin, but it is often believed that it was coined from a Peanuts comic strip about Halloween in 1951. And according to the National Retail Association, Halloween is the second largest commercial holiday—American people spend an average total of $3.1 billion a year on candy alone.

Have a happy Halloween and have fun trick-or-treating!