The Lonely Mountain or Sindarin Erebor is a mountain in the northeast of Rhovanion. When the dwarves had to leave their ancient home Khazad-dûm, it became the new home of Durin's folk. They were led by Thráin I, who became "King under the Mountain". Later Erebor was attacked by the dragon Smaug, and the dwarves had to flee again. In the story told in "The Hobbit", the dragon Smaug is killed and the dwarves again return to the Lonely Mountain. Dáin II Ironfoot becomes new King under the Mountain.