Hallowe'en

In ancient Britain and Ireland, the Celtic festival of Samhain eve was
observed on October 31, at the end of summer. This date was also the eve of
the new year in both Celtic and Anglo-Saxon times and was the occasion for
one of the ancient fire festivals when huge bonfires were set on hilltops to
frighten away evil spirits. The date was connected with the return of herds
from pasture, and laws and land tenures were renewed. The souls of the dead
were thought to revisit their homes on this day, and the autumnal festival
acquired sinister significance, with ghosts, witches, hobgoblins, black
cats, fairies, and demons of all kinds said to be roaming about. It was the
time to placate the supernatural powers controlling the processes of nature.
In addition, Halloween was thought to be the most favourable time for
divinations concerning marriage, luck, health, and death.