Chapter 15 in The Silmarillion

Turgon is shown the way to a hidden valley called Tumladen by Ulmo

The valley is only accessible to eagles and those who know a path under the mountains.

In the center is a hill on which Turgon decides to build a city.

Ulmo builds the city while Turgon rules in Nevrast.

The city is named Gondolin which means “The Hidden Rock.”

Armor and a sword are left behind in Nevrast for an unnamed hero.

Turgon is warned by Ulmo then is sealed in his valley.

The city is given protection by Ulmo and his rivers.

Turgon and his people disappear to the city which remaines unknown to the rest of Middle-Earth.

The city is made of bright stone and stands on a steep hill in the center of the Vale of Tumladen, which was once a lake. Only the eagles by air can enter the valley.

Queen Melian, a Maia Sindarin elf married to King Thingol of Doriath, convinces Galadriel to reveal parts of the Noldor’s history.

Galadriel tells Melian of the Silmarils which troubles the Queen.

She leaves out the Kinslaying and the burning of the ships at Losgar.

Melian tells Thingol, who suspects there is more to the story.

Rumors of evil deeds done by the Noldor spread all the way to Círdan the shipwright and other elves throughout Middle-Earth.

Several Noldor, sons of Finarfin and brothers of Galadriel, visit Doriath.

Thingol confronts them and most do not defend themselves for fear of further incrimination.

One of them, Angrod, defends his actions and becomes angry at the Sindarin king.

Thingol becomes furious but will not harm them due to their value in the war against Morgoth’s forces.

Angrod tells the whole truth of the Noldor’s past, including the Kinslaying, the burning of the ships, and the crossing of the ice.

Thingol exiles the Noldor and all but eradicates their language.