The Silmarillion

In the Great Battle and the tumults of the fall of Thangorodrim there were mighty convulsions in the earth, and Beleriand was broken and laid waste; and northward and westward many lands sank beneath the waters of the Great Sea. In the east, in Ossiriand, the walls of Ered Luin were broken, and a great gap was made in them towards the south, and a gulf of the sea flowed in. Into that gulf the River Lhûn fell by a new course, and it was called therefore the Gulf of Lhûn. That country had of old been named Lindon by the Noldor, and this name it bore thereafter; and many of the Eldar still dwelt there, lingering, unwilling yet to forsake Beleriand where they had fought and laboured long. Gil-galad son of Fingon was their king, and with him was Elrond Half-elven, son of Eärendil the Mariner and brother of Elros first king of Númenor.

Upon the shores of the Gulf of Lhûn the Elves built their havens, and named them Mithlond; and there they held many ships, for the harbourage was good. From the Grey Havens the Eldar ever and anon set sail, fleeing from the darkness of the days of Earth; for by the mercy of the Valar the Firstborn could still follow the Straight Road and return, if they would, to their kindred in Eressëa and Valinor beyond the encircling seas.

Others of the Eldar there were who crossed the mountains of Ered Luin in that age and passed into the inner lands. Many of these were Teleri, survivors of Doriath and Ossiriand; and they established realms among the Silvan Elves in woods and mountains far from the sea, for which nonetheless they ever yearned in their hearts. Only in Eregion, which Men called Hollin, did Elves of Noldorin race establish a lasting realm beyond the Ered Luin. Eregion was nigh to the great mansions of the Dwarves that were named Khazad-dûm, but by the Elves Hadhodrond, and afterwards Moria. From Ost-in-Edhil, the city of the Elves, the highroad ran to the west gate of Khazad-dûm, for a friendship arose between Dwarves and Elves, such as has never elsewhere been, to the enrichment of both those peoples. In Eregion the craftsmen of the Gwaith-i-Mírdain, the People of the Jewel-smiths, surpassed in cunning all that have ever wrought, save only Fëanor himself; and indeed greatest in skill among them was Celebrimbor, son of Curufin, who was estranged from his father and remained in Nargothrond when Celegorm and Curufin were driven forth, as is told in the Quenta Silmarillion.

Elsewhere in Middle-earth there was peace for many years; yet the lands were for the most part savage and desolate, save only where the people of Beleriand came. Many Elves dwelt there indeed, as they had dwelt through the countless years, wandering free in the wide lands far from the Sea; but they were Avari, to whom the deeds of Beleriand were but a rumour and Valinor only a distant name. And in the south and in the further east Men multiplied; and most of them turned to evil, for Sauron was at work.

Seeing the desolation of the world, Sauron said in his heart that the Valar, having overthrown Morgoth, had again forgotten Middle-earth; and his pride grew apace. He looked with hatred on the Eldar, and he feared the Men of Númenor who came back at whiles in their ships to the shores of Middle-earth; but for long he dissembled his mind and concealed the dark designs that he shaped in his heart.

Men he found the easiest to sway of all the peoples of the Earth; but long he sought to persuade the Elves to his service, for he knew that the Firstborn had the greater power; and he went far and wide among them, and his hue was still that of one both fair and wise. Only to Lindon he did not come, for Gil-galad and Elrond doubted him and his fair-seeming, and though they knew not who in truth he was they would not admit him to that land. But elsewhere the Elves received him gladly, and few among them hearkened to the messengers from Lindon bidding them beware; for Sauron took to himself the name of Annatar, the Lord of Gifts, and they had at first much profit from his friendship. And he said to them: "Alas, for the weakness of the great! For a mighty king is Gil-galad, and wise in all lore is Master Elrond, and yet they will not aid me in my labours. Can it be that they do not desire to see other lands become as blissful as their own? But wherefore should Middle-earth remain for ever desolate and dark, whereas the Elves could make it as fair as Eressëa, nay even as Valinor? And since you have not returned thither, as you might, I perceive that you love this Middle-earth, as do I. Is it not then our task to labour together for its enrichment, and for the raising of all the Elven-kindreds that wander here untaught to the height of that power and knowledge which those have who are beyond the Sea?'