During the Fourth Age, which began after the destruction of Mordor and Sauron, Dwarves and Men reforged their friendship. Dáin was killed during the War of the Ring, and was succeeded by his son Thorin III Stonehelm who ruled well into the Fourth Age. During this time, Dwarves from the Lonely Mountain helped rebuild cities in Gondor and the fortress of the Hornburg, and some went to the newly established Dwarven realm of the Glittering Caves where Gimli was lord. The Kingdom of the Lonely Mountain apparently continued to prosper throughout the Fourth Age.[4][5] Subsequently, Gimli went on many undocumented travels with his friend Legolas. It was rumored that in FO 120, Gimli and Legolas boarded a ship that sailed down the river Anduin, and then sailed to Valinor . Gimli was thus the only Dwarf to ever be permitted to cross to the Undying Lands.
Durin VII (the Last), retook Moria and brought Khazad-dûm back to its original splendor, and the Longbeards lived there till the "world grew old and the days of Durin's race ended."
