A lot of people are not aware that the tradition to start wearing Halloween costumes has started a long time ago. This was a tradition that was started out by the Celtic Festival of Samhain. People believed then that they can prevent evil spirits from making an appearance as long as they would light up some bonfires and make sure that ghosts will be warded off.
This may have occurred between 4th century to 7th century AD. Halloween has started to become more commercialized around the 1900s in various parts of the world. People started dressing up for fun without realizing that this is done for a completely different purpose.