From the Gest of Lindiriel & Ioron
Then the house of Finwë and Ingwë's folk crossed the mountains into the lands beyond and thence to Beleriand that lies now beneath the waves. But the Teleri did not follow and in time Lenwë turned his portion of that people south by Anduin the Great.
Now sister and brother there were of Lenwë's house. Her name was Lindiriel, which is "She Who Sings". To me yet the memory of her voice beneath the stars is deep as draughts of miruvorë in the West. Yet ever was her singing keened with sadness, as if she bore foreknowledge of what would pass.
Ioron her brother bore it ill that Lenwë would not dare the mountains, for ever was he bold of temper and he had friends beside amongst Finwë's band. Therefore against all counsel and his lord's command Ioron left his folk upon the road and followed after. And for love of her brother went Lindiriel with him.
Only by dint of stern will and long journey did they find the High Pass and descend into the lands west of the mountains. Then Lindiriel sang for joy at the land that lay before them and she named it unto herself Aldarear the Sea of Trees. For in those days there marched one forest westward to the edge of seeing.
And Ioron called to those who had gone before. But they had not tarried and no answer came back to Ioron save the echo of his own voice. Then doubt entered his heart for the first time, though there might be no returning across the Towers of Mist.
They descended to the plateau that is called Dor-in-Edhel, Place of the Elves, and found - by chance, as Men would say - a bright stream chattering in its bed.
And Lindiriel named that place Ialindë, Song of the Abyss
Following the stream they came upon a gaping cleft and there the crystal waters fell tumbling far into the void. And Lindiriel named that place Ialindë, Song of the Abyss, for it seemed she heard a music in the tumult that stirred yearnings strange within her and she desired to descend if they might into the cleft.
Nothing Ioron heard but the thunder of the waters yet for her sake seven times essayed the climb and seven times returned to her dismayed. For the walls fell sheer upon either side and would not suffer to be scaled.
Then Lindiriel sheared short her hair and from the tresses wove a rope fine and strong. And with that rope they entered the abyss.
Beneath the plain they found a vaulted gorge, so narrow that the floor was scarcely lit by starlight from above. Yet by strange plants shimmering with cold light and by rocks that palely glowed was the gloom relieved. But nothing more could Lindiriel hear of the theme she had heard in the waters, though ever the torrent roaring fell from the plain above, then boiled and spilled away into the darkness.
Silent she sat beside the falls or lost in thought walked the vale beside the bubbling stream. But in sleep she would cry, waking her brother with strange words sung in unknown tongues.
One morning as if still in dream Lindiriel arose and led her brother by a narrow stair to a chamber high behind the falls. The roof and walls and floor were all of pale crystal wrought and the play of starlight through the water threw rainbow flames about the hall.
Then Lindiriel for joy and overweening love sang out aloud and her voice went forth, becoming one with the water and the crystal hall and the jewelled lights that played about the hall. And each in the other found an echo and a common theme that rose and swelled and rising blossomed like a flower enfolding both the Children in its glory.
For by grace had Lindiriel invoked a part of the Music that the Ainur sang into the foundations of the world in the time of its making. And this was by star and water, air and crystal fire and by the voice of a Child of Eru called into being, focused and magnified in the Chamber of Singing Lights.
What was revealed to Lindiriel is not told. For she, her spirit overwhelmed, never spoke in words nor sang again. Nor for all her brother's pleading would she depart the hall but by the curtained water sat and gazed as one transfixed.
for strange and terrible were the things he had beheld
But Ioron was cast in doubt and fear, for strange and terrible were the things he had beheld, half-glimpsed and echoed in the dizzying Song. Neither would he share his heart with Lindiriel but for long years in silence kept watch over her, leaving only at need to forage for himself.
Nourishment she neither craved nor took, but a little of the water she would drink at times. And - slow though it would seem to mortal eyes - the spirit of Lindiriel, lost deep in memory of the Song, o'erwhelmed her body which was all consumed.
Long she remained in spirit in the hall behind the falls and still Ioron would desert her not. But on a time he came and called to her but she dwelt there no longer.
Maybe her spirit had at last joined the falling waters and with them passed through the valley and on at last unto the Sea. Yet some in later days have heard her voice within the falls and an echo of the Music that she sang. For the Wise hold that the Music will once more echo in the crystal hall before the End. And for this the Lord and Lady have worked down the long years.
But Ioron's spirit, long in doubt and guilt combined, worked upon his body in another way. Aged and worn in aspect he became. Thus he is named Ioron, "the Old One", who first of all the Firstborn endured the frailty of Arda.
And at last Ioron departed the valley and across the broad lands wandered, calling for Lindiriel his sister like a soul bereft. Thus did the Naugrim come upon him.