§ Of Maeglin The Silmarillion

In that wood in ages past Melian walked in the twilight of Middle-earth when the trees were young, and enchantment lay upon it still. But now the trees of Nan Elmoth were the tallest and darkest in all Beleriand, and there the sun never came; and there Eöl dwelt, who was named the Dark Elf. Of old he was of the kin of Thingol, but he was restless and ill at ease in Doriath, and when the Girdle of Melian was set about the Forest of Region where he dwelt he fled thence to Nan Elmoth. There he lived in deep shadow, loving the night and the twilight under the stars. He shunned the Noldor, holding them to blame for the return of Morgoth, to trouble the quiet of Beleriand; but for the Dwarves he had more liking than any other of the Elvenfolk of old. From him the Dwarves learned much of what passed in the lands of the Eldar.