§ Of Beren and Lúthien The Silmarillion

Upon all that plain the Elves of Nargothrond kept unceasing watch; and every hill upon its borders was crowned with hidden towers, and through all its woods and fields archers ranged secretly and with great craft. Their arrows were sure and deadly, and nothing crept there against their will. Therefore, ere Beren had come far upon his road, they were aware of him, and his death was nigh. But knowing his danger he held ever aloft the ring of Felagund; and though he saw no living thing, because of the stealth of the hunters, he felt that he was watched, and cried often aloud: 'I am Beren son of Barahir, friend of Felagund. Take me to the King!' Therefore the hunters slew him not, but assembling they waylaid him, and commanded him to halt. But seeing the ring they bowed before him, though he was in evil plight, wild and wayworn; and they led hi northward and westward, going by night lest their paths should be revealed. For at that time there was no ford or bridge over the torrent of Narog before the gates of Nargothrond; but further to the north, where Ginglith joined Narog, the flood was less, and crossing there and turning again southward the Elves led Beren under the light of the moon to the dark gates of their hidden halls.