Samhain marked the end of the harvest season and beginning of winter or the 'darker half' of the year. It was seen as a liminal time, when the boundary between this world and the Otherworld thinned. This meant the Aos Sí, the 'spirits' or 'fairies', could more easily come into this world and were particularly active.

In fact, the origins of Halloween began over 2,000 years ago with the Celts celebrating the pagan holiday known as Samhain, which marks the beginning of winter. This time of year was believed to be when the veil between the dead and the living was the thinnest and people would wear disguises to ward off spirits.

Halloween began as a the Festival of Samhain about 2,000 years ago. It was created as a way for the Celts to scare away ghosts and spirits. They believed around that time of the year, the wall between their realm and ours thinned.