Folk under the Mountain

Náin I was the last King of Durin's Folk to rule in Khazad-dûm after the awakening of the Balrog beneath the Misty Mountains. Náin was slain by that Balrog, and his son Thráin I abandoned his ancient mansions and led his people out into Middle-earth. They journeyed far to the north and east until they come upon a single peak standing out from the surrounding plains. This was the Lonely Mountain, and in III 1999 Thráin founded a new kingdom of Dwarves beneath it. Thráin's new realm became known as the Kingdom under the Mountain, and its people were the Folk under the Mountain.

This first occupation of Erebor (as the Lonely Mountain was known in the Elvish tongue) lasted a little over two centuries. In III 2210, Thráin's son Thorin I sought out a new home for his numerous people, leaving the Lonely Mountain behind to settle in the Grey Mountains to the west.

For nearly four hundred years, the Kingdom under the Mountain was abandoned by the Dwarves, or at least by their royal line and most of their folk. In the year III 2590, however, the Dwarves returned. During their time in the Grey Mountains, their wealth had drawn the unwelcome attention of the Dragons, and King Dáin I, a descendant of Thorin I, had been slain by a Cold-drake. Dáin's son Thrór set out to seek a safer stronghold, and led his people back to Erebor to become Folk under the Mountain once again. Not all of the Dwarves returned to Erebor at this time: Thrór's younger brother Grór led many of their people farther eastward still, to settle in the range of the Iron Hills.

Beneath the Lonely Mountain, the Dwarves prospered for nearly two centuries, but the threat of the Dragons that had driven them from the Grey Mountains still remained. In III 2770 the Dragon Smaug descended from the North and sacked Erebor, claiming its treasures for himself. Few of the Dwarves survived Smaug's attack, but King Thrór and his family were among those that escaped, travelling into exile from the lost Lonely Mountain.

Over the years that followed, the Dwarves were beset by tragedy and war, but through all this Thrór's grandson Thorin Oakenshield nursed a hunger for revenge against the Dragon Smaug. In III 2941, 171 years after the loss of Erebor, Thorin took action. He assembled a company of Dwarves and, accompanied by the Wizard Gandalf and the Hobbit Bilbo Baggins, they made the perilous journey across Middle-earth to reclaim the Lonely Mountain from the Dragon.

Thorin's Quest of Erebor succeeded, but it culminated in the Battle of Five Armies in which Thorin himself was slain, alongside his heirs Fíli and Kíli. With Thorin's line at an end, the Kingship of Durin's Folk fell on the heir of Grór, the brother of Thrór who had long ago settled in the Iron Hills. This heir was Dáin Ironfoot, and Dáin thus re-established the Folk under the Mountain for the third time in their history. Once again they prospered, building an alliance with the Men of Dale and Esgaroth who lived nearby. They came close to defeat in the War of the Ring, which saw King Dáin fall in battle and the Lonely Mountain besieged. The Folk of the Mountain survived these hardships and continued to thrive beneath their Mountain into the Fourth Age.