Ireland was ruled by the bloodthirsty, superstitious pagan Druids.
Thomas Cahill wrote in How the Irish Saved Civilization(Random House, 1995):
“Romans, in their first encounters with these exposed, insane warriors, were shocked and frightened … They were howling and, it seemed, possessed by demons, so outrageous was their strength … featuring all the terrors of hell itself.”
The Druids, from whom Halloween originated, believed that the trees and hills were inhabited by good and evil spirits which had to be appeased.