By the old Celtic calendar, October 31 was the end of the year, the night of witches, the threshold life crossed into the dark, cold dead of winter, the night when ghosts and supernatural creatures haunted moor, loch and plain. Marsh fire, later known as "jack-of-the-latern," shimmered in dank bogs where many of the dead, human sacrifices lay buried. Later, children went from house to house begging for blocks of peat for fires to keep the night at bay. Ancient Scots bobbed for apples. And those born on October 31 were reputed to have second sight and magic powers.
The Christian era eventually blunted much of the night's forces, and it became All Hallow's Eve (hallow meaning holy), ushering in All Saints Day, November 1.
(source: Scott Blakey, Entertainment News Service)