 They were the first to cross the Ered Luin in the Years of the Trees, and established strongholds in Beleriand before the building of Nogrod and Belegost in the Blue Mountains, and before the Elves arrived.These very ancient settlements were at Nargothrond and Amon Rûdh.In Beleriand, these dwarves diminished in physical stature and smith-craft.