Thror

Thror, often written Thrór in older texts, is a fictional character in J. R. R. Tolkien's legendarium. He is a Dwarf of Durin's Folk and the King under the Mountain who ruled the kingdom of Erebor, the Lonely Mountain, during the early Third Age.

Thror was the father of Thrain and the grandfather of Thorin Oakenshield. He is remembered for possessing a map and a key to a hidden entrance to Erebor, tools that later aided his descendants in planning their return.

After Smaug the dragon attacked Erebor, Thror led his people into exile, taking refuge in the Grey Mountains. He died there in exile a number of years later, leaving Thrain to inherit the kingship and the burdens of his father's legacy.

Thror's line continued through Thrain and Thorin, who ultimately reclaimed Erebor as told in The Hobbit, aided by Thorin's company, which included Bilbo Baggins. In Tolkien's published writings, Thrór is mentioned in the appendices and other works detailing the history of Durin's Folk; the name is sometimes spelled Thrór in archaic forms.