The Dead and The Undead

[Morthoron]

In regards to the Dead Marshes, of course Tolkien was referring to his horrid experience in WWI seeing dead bloated soldiers staring lifelessly as they bobbed up from the murky water at the bottom of bomb craters and foxholes: "the Dead Marshes and the approaches to the Morannon owe something to Northern France after the Battle of the Somme."

What is interesting about Tolkien's ghastly reminiscence is that he married his personal horror to folktales of Welsh and Irish origin:

'I don't know,' said Frodo in a dreamlike voice. 'But I have seen them too. In the pools when the candles were lit. They lie in all the pools, pale faces, deep deep under the dark water. I saw them: grim faces and evil, and noble faces and sad. Many faces proud and fair, and weeds in their silver hair. But all foul, all rotting, all dead. A fell light is in them.'

Gollum refers to these lights as "corpse candles", a motif used often in old ghost tales that either act as a precursor to death, or more malevolently led travelers off the road at night and to their watery deaths in bogs and fens, known in legend as the Ignis Fatuus: a light that sometimes appears in the night over marshy ground and is often attributable to the combustion of gas from decomposed organic matter.

As far as the dead themselves, as noted they look grim, evil, noble, sad, proud, fair -- an approximation of their previous lives and personas mirrored below the foul water. They are not animate, they are reflections; although Tolkien never explained why "a fell light was in them."

Tolkien also notes the Dead Marshes "owe more to William Morris and his Huns and Romans in The House of the Wolfings and The Root of the Mountains." Now, it's been decades since I read Morris, so I can't recall in what context Tolkien was referencing, but I do remember how Tolkienish it seemed (in a Rohirric sort of way), and I will always remember "the treasure of the world, the Dwarf-wrought Hauberk." Weird what one retains.