Smaug was the greatest fire-breathing dragon of the Third Age. Sometime in 2880 3A, he attacked the Erebor and the city of Dale. He claimed the treasure of the mountain for himself and forced Thrór, King under the Mountain, and his people into exile. Thorin's quest - with the help of his burglar Bilbo Baggins - to reclaim the treasure ended in success when Smaug was slain by Bard Bowman.