Erebor stands hundreds of miles from the nearest mountain range. Tolkien's rendering of Thrór's map in
The Hobbit shows it with six ridges stretching out from a central peak that was snowcapped well into spring. The whole mountain is some ten miles in diameter; it contains an immense wealth of gold and jewels.
Origins Erebor becomes the home of the Folk of
Durin, a clan of
Dwarves known as the
Longbeards, after they are driven from their ancestral home of
Khazad-dûm. In the latter days of the Third Age, this Kingdom under the Mountain holds one of the largest dwarvish treasure hoards in Middle-earth. The Kingdom under the Mountain is founded by Thráin I the Old, who had discovered the Arkenstone there. His son, Thorin I, leaves the mountain with much of the Folk of Durin to live in the Ered Mithrin (Grey Mountains) on account of the great riches to be found in that range. After
dragons plunder their hoards, the Longbeards, led now by Thrór, a descendant of Thorin, return to Erebor to take up the title King under the Mountain. Under Thrór's reign, Erebor becomes a great stronghold where the dwarves are numerous and prosperous. Bilbo, Thorin, and
Thorin's company of twelve other Dwarves travel to the Lonely Mountain to regain the treasure. They plan to use the secret door, whose key and map Gandalf had obtained from Thráin, whom he had found at the point of death in the pits of
Dol Guldur. Smaug, enraged by the theft, emerges from the mountain and flies south to destroy
Lake-town, which he suspects is the source of the "thieves". During this attack Smaug is killed by
Bard the Bowman; Thorin claims the mountain on learning of Smaug's demise. However, the Men of Esgaroth, supported by
Thranduil and the
Elves of
Mirkwood, march in force to the mountain to demand a part of the dragon's hoard as recompense for the destruction. Thorin, mad with greed, refuses all claims and sends word to his second cousin
Dáin II Ironfoot, chief of the Dwarves of the
Iron Hills, who brings reinforcements. Before battle can begin, an army of
Orcs and
Wargs descends on Erebor. Dwarves, Elves, and Men join ranks against them, leading to the Battle of Five Armies. Thorin's nephews
Fíli and
Kíli are killed, and Thorin is mortally injured; he dies shortly afterwards. The title of King under the Mountain passes to Dáin.
Erebor in The Lord of the Rings With the restoration of the Kingdom under the Mountain, the area becomes prosperous again. Dale is rebuilt under Bard's leadership, and Dwarves and Men reforge their friendship. Some of the Dwarves, led by
Balin, leave Erebor to reclaim the ancient Dwarvish Kingdom of Moria. In the
War of the Ring, an emissary from
Sauron, the lord of
Mordor, twice comes to Erebor and speaks to Dáin. The messenger asks for assistance in finding Bilbo Baggins and retrieving
a stolen ring, and in return offers Moria and three of the
seven Dwarf rings to Dáin, who declines to reply. Sauron's northern army, including many
Easterlings, then attacks; Dale is overrun, and many Dwarves and Men take refuge in Erebor, which is promptly surrounded. Dáin is killed before the gates of Erebor defending the body of his fallen ally King Brand of Dale. Dáin's son Thorin III Stonehelm and King Bard II withstand the siege and rout Sauron's forces. == Analysis ==