Samhain is the celebration of the end of the harvest or the summer’s end.
It was thought to be a time when the door to the Otherworld was opened allowing the souls of the dead to walk freely between worlds and join us in ours. They were even invited to the feast with a place at the table laid out for them.
However, mischievous fairies and evil spirits could also come through and people used to disguise themselves as a form of protection from these malevolent beings. This practice has since evolved into the modern tradition of fancy dress on Halloween.