• in TA c. 1100, the Wise were becoming suspicious of Dol Guldur;
• that in 2063 Gandalf entered Dol Guldur, before whom Sauron was said to retreat taking refuge in the East;
• that Sauron returned to Dol Guldur in 2450;
• and that it was not until 2850 upon Gandalf’s second foray into Sorceror’s Head that he at last fully apprehended that the Necromancer was indeed the ancient foe of Tol‐in‐Gaurhoth, Sauron himself.

There Morgoth’s servants fast him caught
and he was cruelly bound, and brought
to Sauron captain of the host,
the lord of werewolf and of ghost,
most fowl and fell of all who knelt
at Morgoth’s throne. In might he dwelt
on Gaurhoth Isle; but now had ridden
with strength abroad, by Morgoth bidden
to find the rebel Barahir.

[...]

      To Nargothrond no more he came
but thither swiftly ran the fame
of their dead king and his great deed,
how Lúthien the Isle had freed:
the Werewolf Lord was overthrown,
and broken were his towers of stone.
For many now came home at last
who long ago to shadow passed;
and like a shadow had returned
Huan the hound, though scant he earned
or praise or thanks of Celegorm.

      Men called him Thû, and as a god
in after days beneath his rod
bewildered bowed to him, and made
the ghastly temples in the shade.
Not yet by Men enthralled adored,
now was he Morgoth’s mightiest lord,
Master of Wolves, whose shivering howl
for ever echoed in the hills, and foul
enchantments and dark sigaldry
did weave and wield. In glamoury
that necromancer held his hosts
of phantoms and of wandering ghosts,
of misbehotten or spell‐wronged
monsters that about him thronged,
working his bidding dark and vile:
the werewolves of the Wizard’s Isle.

Nigh the foul spirit Morgoth made
and bred of evil shuddering strayed
from its dark house, when Lúthien rose
and shivering looked upon his throes.

      ‘O demon dark, O phantom vile
of foulness wrought, of lies and guile,
here shalt thou die, thy spirit roam
quaking back to thy master’s home
his scorn and fury to endure
thee he will in the bowels immure
of groaning earth, and in a hole
everlasting thy naked soul
shall wail and gibber—this shall be,
unless the keys thou render me
of thy black fortress, and the spell
that bindeth stone to stone thou tell,
and speak the words of opening.’

      With gasping breath and shuddering
he spake, an yielded as must,
and vanquished betrayed his master’s trust.

      Lo! by the bridge a gleam of light
like star descended from the night
to burn and tremble here below.
There wide her warms did Lúthien throw
and called aloud with voice as clear
as still at whiles may mortal hear
long elvish trumpets o’er the hill
echo, when all the world is still.
      The dawn peered over mountains wan,
their grey heads silent looked thereon.
The hill trembled; the citadel
crumbled, and all its towers fell;
the rocks yawed and the bridge broke,
And Sirion spumed in sudden smoke.
      Like ghosts the owls were flying seen
hooting in the dawn, and bats unclean
went skimming dark through the cold airs
shrieking thinly to find new lairs
in Deadly Nightshade’s branches dread.
The wolves whimpering and yammering fled
like dusky shadows. Out there creep
pale forms and ragged as from sleep,
crawling, and shielding blinded eyes:
the captives in fear and in surprise
from dolour long in clinging night
beyond all hope set free to light.

The Lay of Leithian, 2770–2815