Thráin I (Third Age 1934 – 2190, died aged 256) was the King of Durin's Folk for 209 years, succeeding his father, Náin I, when he was killed by the Balrog in T.A. 1980. Thráin founded the Kingdom under the Mountain at Erebor, and was a descendent of Durin the Deathless via his grandfather Durin VI.
Thráin's grandfather, Durin VI, was King of Khazad-dûm when the Balrog of Morgoth appeared in Moria; the Balrog has forever been known as Durin's Bane as Durin was killed by it in T.A. 1980. Durin's son - and Thráin's father - Náin I was now King and he attempted to hold out against the Balrog but was himself killed in T.A. 1981, being the last true King of Khazad-dûm until Durin VII and Last in the Fourth Age.
Thráin - at the tender age of 47 - became King of Durin's Folk. He led his wandering people until T.A. 1999 when he founded the Kingdom under the Mountain in Erebor. In Erebor the Dwarves began building a mighty kingdom, discovering the prized possession of King Thráin: the Arkenstone, the Heart of the Mountain.
Thráin died in T.A. 2190 at the age of 256 and was succeeded by his son Thorin I. With a rule of 209 years, Thráin I is the longest-ruling of all the known Kings of Durin's Folk with, perhaps, the only exception being Durin the Deathless.
|King of Durin's Folk
T.A. 1981 – 2190
|1st King under the Mountain
T.A 1999 – 2190