 It was the only one of the Dwarf-mansions to survive the First Age.Far to the west of Khazad-dûm, the great dwarvish cities of Belegost and Nogrod were founded in Ered Luin (the Blue Mountains) during the Years of the Trees, before the arrival of the Elves in Beleriand.The Dwarves of Belegost were the first to forge mail of linked rings, and they also traded weaponry with the Sindar and carved the Thousand Caves of Menegroth for the Elf king Thingol.