Smaug

Smaug was the last of the great fire-drakes, and said to be the greatest dragon of his time. At some time during the twenty-eighth century of the Third Age, he came to hear of the immense wealth held by the Dwarves of Erebor. Where he came from we do not know for certain, but in the year III 2770 he descended in fire on the Lonely Mountain, destroying the Dwarf-kingdom and the nearby township of Dale.

Sources

Smaug at Encyclopedia of Arda