Halloween’s Origins Celtic New Year’s Celebration originally called Samhain (‘Summer’s End’) October 31: when Druids warded off the hostile ghosts of the recently dead by opening their doors, offering bonfires and gifts of food to these returning dead Later dressed as ghosts themselves to shield themselves from the ghosts’ mischief The Celtic lunar calendar consisted of 13 months of 28 days each - plus one extra day to make 365 days.