Morgoth, I believe, means "Black Enemy."
Sauron use the title "Dark Lord" when he chants his Ring-spell, if not before.
Later he implicitly acknowledges Morgoth's continuing existence when he teaches
the Numenoreans to worship Morgoth who is not destroyed but simply exiled to
the outer darkness. Was Sauron's use of "Dark Lord" an arrogant usurpation of
his old master's title and position, or was it a new appellation he gave
himself, or is Dark Lord so generic a phrase that it is meaningless to say who
is the "real" Dark Lord?
I must say I always have thought the Barrow Wight is referring to Morgoth in
his spell invoking the "Dark Lord's" second coming.
Morgoth's attack on Gondolin in Tolkien's first rendering, done during WWI, is
a fairly obvious transferral of that war's machinery of mass death into
mythological form: tanks, flamethrowers, etc. all figure in the story. Later
Tolkien (older and wiser) pulled back from such obvious
allegory.
Old be web and board and post,
and old be snert unto boast:
never more to talk of subjects new,
never, till PJ's thin and the Moon is blue.
On bad art the threads shall grow fat,
and still on TORn here let them chat,
till the Purist vents his spleen
over dead book and silver screen.
