The Silmarillion

It has been told that Huor the brother of Húrin was slain in the Battle of Unnumbered Tears; and in the winter of that year Rían his wife bore a child in the wilds of Mithrim, and he was named Tuor, and was taken to foster by Annael of the Grey-elves, who yet lived in those hills. Now when Tuor was sixteen years old the Elves were minded to leave the caves of Androth where they dwelt, and to make their way secretly to the Havens of Sirion in the distant south; but they were assailed by Orcs and Easterlings before they made good their escape, and Tuor was taken captive and enslaved by Lorgan, chief of the Easterlings of Hithlum. For three years he endured that thraldom, but at the end of that time he escaped; and returning to the caves of Androth he dwelt there alone, and did such great hurt to the Easterlings that Lorgan set a price upon his head.

But when Tuor had lived thus in solitude as an outlaw for four years, Ulmo set it in his heart to depart from the land of his fathers, for he had chosen Tuor as the instrument of his designs; and leaving once more the caves of Androth he went westwards across Dor-lómin, and found Annon-in-Gelydh, the Gate of the Noldor, which the people of Turgon built when they dwelt in Nevrast long years before. Thence a dark tunnel led beneath the mountains, and issued into Cirith Ninniach, the Rainbow Cleft, through which a turbulent water ran towards the western sea. Thus it was that Tuor's flight from Hithlum was marked by neither Man nor Orc, and no knowledge of it came to the ears of Morgoth.

And Tuor came into Nevrast, and looking upon Belegaer the Great Sea he was enamoured of it, and the sound of it and the longing for it were ever in his heart and ear, and an unquiet was on him that took him at last into the depths of the realms of Ulmo. Then he dwelt in Nevrast alone, and the summer of that year passed, and the doom of Nargothrond drew near; but when the autumn came he saw seven great swans flying south, and he knew them for a sign that he had tarried overlong, and he followed their flight along the shores of the sea. Thus he came at length to the deserted halls of Vinyamar beneath Mount Taras, and he entered in, and found there the shield and hauberk, and the sword and helm, that Turgon had left there by the command of Ulmo long before; and he arrayed himself in those arms, and went down to the shore. But there came a great storm out of the west, and out of that storm Ulmo the Lord of Waters arose in majesty and spoke to Tuor as he stood beside the sea. And Ulmo bade him depart from that place and seek out the hidden kingdom of Gondolin; and he gave Tuor a great cloak, to mantle him in shadow from the eyes of his enemies.

But in the morning when the storm was passed, Tuor came upon an Elf standing beside the walls of Vinyamar; and he was Voronwë, son of Aranwë, of Gondolin, who sailed in the last ship that Turgon sent into the West. But when that ship returning at last out of the deep ocean foundered in the great storm within sight of the coasts of Middle-earth, Ulmo took him up, alone of all its mariners, and cast him onto the land near Vinyamar; and learning of the command laid upon Tuor by the Lord of Waters Voronwë was filled with wonder, and did not refuse him his guidance to the hidden door of Gondolin. Therefore they set out together from that place, and as the Fell Winter of that year came down upon them out of the north they went warily eastward under the eaves of the Mountains of Shadow/

At length they came in their journeying to the Pools of Ivrin, and looked with grief on the defilement wrought there by the passage of Glaurung the Dragon; but even as they gazed upon it they saw one going northward in haste, and he was a tall Man, clad in black, and bearing a black sword. But they knew not who he was, nor anything of what had befallen in the south; and he passed them by, and they said no word.

And at the last by the power that Ulmo set upon them they came to the hidden door of Gondolin, and passing down the tunnel they reached the inner gate, and were taken by the guard as prisoners. Then they were led up the mighty ravine of Orfalch Echor, barred by seven gates, and brought before Ecthelion of the Fountain, the warden of the great gate at the end of the climbing road; and there Tuor cast aside his cloak, and from the arms that he bore from Vinyamar it was seen that he was in truth one sent by Ulmo. Then Tuor looked down upon the fair vale of Tumladen, set as a green jewel amid the encircling hills; and he saw far off upon the rocky height of Amon Gwareth Gondolin the great, city of seven names, whose fame and glory is mightiest in song of all dwellings of the Elves in the Hither Lands. At the bidding of Ecthelion trumpets were blown on the towers of the great gate, and they echoed in the hills; and far off but clear there came a sound of answering trumpets blown upon the white walls of the city, flushed with the rose of dawn upon the plain.