It is told among the Eldar that Beren and Lúthien returned to the northern lands and dwelt together as living man and wife, and they went again into Doriath. Those that saw them were both glad and afraid, for Beren had returned as mortal Man from the Dead, but Lúthien healed the winter of Thingol's grief with the touch of her hand. But Melian, looking into her eyes, read the doom that had befallen her in the West and looked away, and never has there been such a grief of loss as befell Melian the Maia in that hour, for she knew then that a parting beyond the Circles of the World had come between them. And so, Beren and Lúthien went then alone to Tol Galen, the Green Isle in Ossiriand, and all tidings of them ceased. The Eldar named that land Dor Firn-i-Guinar, that is, The Land of the Dead that Live, and there was born Dior Eluchíl, the beautiful, and the heir of Thingol. Beren spoke no more with mortal Man, and none saw where the twain left the world, nor marked where their bodies lay.
In those days, Maedhros son of Fëanor, perceiving the wondrous deeds of Beren and Lúthien, lifted up his heart, for he saw that Morgoth was not unassailable. Yet he perceived also that Morgoth would smoke them all out one by one if they did not make common counsel and union, and so he began those plans for the raising of the fortunes of the Eldar which are called the Union of Maedhros. But the Oath of Fëanor and the evil deeds of that House wrought injury to his designs and he had less aid than should have been. Orodreth, lord of Nargothrond, would render no aid whatever to any Son of Fëanor (because of the deeds of Celegorm and Curufin), and for the most part the Gnomes of Nargothrond trusted still to maintain their domain by secrecy and hidden dart. However, Gwindor son of Guilin, remembering the Dagor Bragollach and the loss of his brother Gelmir, marched forth (against the will of Orodreth) beneath the banner of Fingon.
From Doriath came little aid, again because of the Oath. Maedhros had before sent messages to Thingol with haughty words reminding the woodland king of the Sons' claim to the Silmaril, summoning him to yield the holy jewel or become their enemy. Melian counselled the king to give it up, but Thingol, having become fast-bound to the Silmaril and mindful of the sufferings of Beren and Lúthien (and again because of the merciless deeds of Celegorm and Curufin). And so he sent messengers with scornful words to the Sons. Maedhros did not reply, being busy with counsels of war, but Celegorm and Curufin vowed openly to slay Thingol and destroy his kingdom if they returned victorious from the war and the Silmaril were not given up freely. And so Thingol fortified the confines of Doriath and none save Beleg and Mablung went forth to war. To them Thingol gave leave to go, so long as they marched under the banner of Fingon and served not the Sons of Fëanor.
The Dwarves of Nogrod and Belegost rendered service to Maedhros, and the mountain smithies were busy in those days. All the Sons of Fëanor, and all who would follow them, were marshalled then, and the Men of Bór and Ulfang the Easterling were enlisted. In the West, Fingon gathered together the remnant of his people and called together the people of Himring, and in Hithlum the Gnomes and the Men of Hador's House prepared for war. In the woods of Brethil, Haldir, son of Helmir (who died ere the war began), marshalled his people. Word of these counsels came beyond the mountains even to Gondolin.
But Morgoth was aware of well-nigh all that was done, and he took counsel against Maedhros. Spies and other workers of treachery he dispatched then into Beleriand, and the Men of his secret allegiance were yet deep within the counsels of the Gnomes. But Maedhros, having called together all strength of Elves, Men and Dwarves that he could, counselled to assault Angband from east and west. He purposed to march across Anfauglith with banners in open force, and that when he had lured the hosts of Morgoth across the sands, he purposed that Fingon should come down out of Hithlum upon the West and so they would take the might of Morgoth as between a hammer and and anvil and break it to pieces; and the signal for this would be the firing of a great beacon in Dorthonion...