The Trolls' Cave and the Swords
The HobbitThe encounter with the trolls leads to the discovery of the ancient elven swords Orcrist and Glamdring, which serve the company throughout their quest.
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Bearing strength in each event
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The Trolls' Camp

The Three Trolls
The Trap
Bilbo is caught by the trolls, who then capture the dwarves. They argue over how to cook them, but Gandalf returns and tricks them until dawn turns them to stone.
The Cave
The company searches for the trolls' cave. They find it and discover a hoard of plunder, including swords.
The Swords' Origin
Gandalf and Thorin each take a sword: Glamdring and Orcrist. These are ancient elven blades from Gondolin, made for the Goblin-wars. They are later identified by Elrond.
Elrond's Identification

The Swords' Names
Elrond's Knowledge
Elrond examines the swords and tells their history. Orcrist means "Goblin-cleaver" and Glamdring means "Foe-hammer." They were used in the wars of Gondolin.
The Significance
The swords are feared by goblins. They glow when enemies are near. They become important symbols of the company's heritage.
Thorin's Vow
Thorin vows to use Orcrist against goblins. The swords give the dwarves an edge in future battles.
The Swords in Action

The Swords' Use
In the Goblin Tunnels
Orcrist and Glamdring are used to kill the Great Goblin and many other goblins. The goblins call them "Biter" and "Beater" and fear them.
In the Battle
Thorin uses Orcrist in the Battle of Five Armies. After his death, the Elvenking lays Orcrist on his tomb, where it will glow if enemies approach.
Bilbo's Sting
Bilbo's sword, Sting, also glows blue when goblins are near. It becomes a symbol of his courage. The swords are a gift from the past that aids the present.
Early in the journey, near the Lone-lands
At Rivendell, during the stay
Throughout the journey, from the Misty Mountains to the Battle