The Silmarillion

Under the cold stars before the rising of the Moon the host of Fëanor went up the long Firth of Drengist that pierced the Echoing Hills of Ered Lómin, and passed thus from the shores into the great land of Hithlum; and they came at length to the long lake of Mithrim, and upon its northern shore made their encampment in the region that bore the same name. But the host of Morgoth, aroused by the tumult of Lam-moth and the light of the burning at Losgar, came through the passes of Ered Wethrin, the Mountains of Shadow, and assailed Fëanor on a sudden, before his camp was full-wrought or put in defence; and there on the grey fields of Mithrim was fought the Second Battle in the Wars of Beleriand. Dagor-nuin-Giliath it is named, the Battle-under-Stars, for the Moon had not yet risen; and it is renowned in song. The Noldor, outnumbered and taken at unawares, were yet swiftly victorious; for the light of Aman was not yet dimmed in their eyes, and they were strong and swift, and deadly in anger, and their swords were long and terrible. The Orcs fled before them, and they were driven forth from Mithrim with great slaughter, and hunted over the Mountains of Shadow into the great plain of Ard-galen, that lay northward of Dorthonion. There the armies of Morgoth that had passed south into the Vale of Sirion and beleaguered Círdan in the Havens of the Falas came up to their aid, and were caught in their ruin. For Celegorm, Fëanor's son, having news of them, waylaid them with a part of the Elven-host, and coming down upon them out of the hills near Eithel Sirion drove them into the Fen of Serech. Evil indeed were the tidings that came at last to Angband, and Morgoth was dismayed. Ten days that battle lasted, and from it returned of all the hosts that he had prepared for the conquest of Beleriand no more than a handful of leaves.

Yet cause he had for great joy, though it was hidden from him for a while. For Fëanor, in his wrath against the Enemy, would not halt, but pressed on behind the remnant of the Orcs, thinking so to come at Morgoth himself: and he laughed aloud as he wielded his sword, rejoicing that he had dared the wrath of the Valar and the evils of the road, that he might see the hour of his vengeance. Nothing did he know of Angband or the great strength of defence that Morgoth had so swiftly prepared: but even had he known it would not have deterred him, for he was fey, consumed by the flame of his own wrath. Thus it was that he drew far ahead of the van of his host; and seeing this the servants of Morgoth turned to bay, and there issued from Angband Balrogs to aid them. There upon the confines of Dor Daedeloth, the land of Morgoth, Fëanor was surrounded, with few friends about him. Long he fought on, and undismayed, though he was wrapped in fire and wounded with many wounds; but at the last he was smitten to the ground by Gothmog, Lord of Balrogs, whom Ecthelion after slew in Gondolin. There he would have perished, had not his sons in that moment come up with force to his aid; and the Balrogs left him, and departed to Angband.

Then his sons raised up their father and bore him back towards Mithrim. But as they drew near to Eithel Sirion and were upon the upward path to the pass over the mountains, Fëanor bade them halt; for his wounds were mortal, and he knew that his hour was come. And looking out from the slopes of Ered Wethrin with his last sight he beheld far off the peaks of Thangorodrim, mightiest of the towers of Middle-earth, and knew with the foreknowledge of death that no power of the Noldor would ever overthrow them; but he cursed the name of Morgoth thrice, and laid it upon his sons to hold to their oath, and to avenge their father. Then he died; but he had neither burial nor tomb, for so fiery was his spirit that as it sped his body fell to ash, and was borne away like smoke; and his likeness has never again appeared in Arda, neither has his spirit left the halls of Mandos. Thus ended the mightiest of the Noldor, of whose deeds came both their greatest renown and their most grievous woe.

Now in Mithrim there dwelt Grey-elves, folk of Beleriand that had wandered north over the mountains, and the Noldor met them with gladness, as kinsfolk long sundered; but speech at first was not easy between them, for in their long severance the tongues of the Calaquendi in Valinor and of the Moriquendi in Beleriand had drawn far apart. From the Elves of Mithrim the Noldor learned of the power of Elu Thingol, King in Doriath, and the girdle of enchantment that fenced his realm; and tidings of these great deeds in the north came south to Menegroth, and to the havens of Brithombar and Eglarest. Then all the Elves of Beleriand were filled with wonder and with hope at the coming of their mighty kindred, who thus returned unlocked-for from the West in the very hour of their need, believing indeed at first that they came as emissaries of the Valar to deliver them.