From earliest times people wore masks when droughts or other disasters struck. They believed that the demons who had brought their misfortune upon them would become frightened off by the hideous masks. Even after the festival of Samhain had merged with Halloween, Europeans felt uneasy at this time of the year. Food was stored in preparation for the winter and the house was snug and warm. The cold, envious ghosts were outside, and people who went out after dark often wore masks to keep from being recognised.
Myself I always loved the idea that at this time of the year like no other I could don a costume and mask and be unknown for a night. When I was a kid I loved going to one of th big retail chains and seeing the boxes upon boxes of plastic halloween masks. Yes they actually came in boxes! Check out a few of these vintage masks. Ah the memories.