The Quick Answer
Costumes connect to old customs of disguising and 'mumming' around Samhain and All Hallows', and became a playful celebration in North America in the 1900s.
The Story
In Ireland, Scotland and Britain, people sometimes went door to door in disguise ('guising'), performing in exchange for food. Some folklore says disguises helped people hide from wandering spirits. Commercial costumes spread in the early 1900s.
Legend vs. History
The idea that costumes were mainly to confuse ghosts is a popular explanation; historians see it as one of several possible reasons.
Tell the Kids
“A long time ago, people dressed up and went visiting to sing or tell jokes for treats. Now we dress up for fun!”
Did You Know?
Early costumes were often homemade from sheets, masks and whatever people had at home.
Try This Tradition
Have a 'thrift costume' challenge — everyone makes a costume from things already in the house.