The word 'troll' is of Nordic origin, and in the fairy-tales of Northern Europe it is supposed to have been a human-like, mischievous and hairy dwarf who swaps troll children for human children in the middle of the night. For good measure, trolls are sometimes depicted as equally mischievous and hairy giants, some of whom lived under bridges or in caves. Which would be all well and good but for the singular observation that the word 'troll' is entirely absent from the original Anglo-Saxon text of Beowulf!
