Frozen Fortress and Capital of Angmar
“The Witch-king established Carn Dûm as the chief fortress of the North Kingdom of Angmar
and populated it with Men of Darkness, Orcs, and other fell creatures.”
Early in the years of the second millennium of the Third Age, the Lord of the Nazgûl was sent north by the Dark Lord to establish the realm of Angmar. Sauron saw the disunion of Arnor into the three smaller kingdoms of Arthedain, Cardolan and Rhudaur and sent his emissary north to weaken and destroy them. The Witch-king of Angmar as he was called in the north, built the great fortress of Carn Dûm in the frozen heights of the Misty Mountains, upon the western tip of the range called the Mountains of Angmar. There he gathered a vast army of the servants of shadow and made war upon what remained of the North Kingdom.
For over 600 years war raged across the north of Middle-earth, which was also decimated by a great plague that came out of the East. Finally, in the year 1974 of the Third Age, Fornost fell and the North Kingdom was utterly destroyed. A great fleet was sent north out of Gondor and drove the Witch-king from his lair in Angmar, but it was too late to save Arnor.
Very little is known about this vast fortress of darkness, for none now live who remember it. However, looking at the Dead City of Minas Morgul, one can surmise that Carn Dûm was also place of shadow and death, ruled by fear and the power of the Nazgûl, who in turn were the manifestation of the power of their Dark Master in Mordor.
The capital of Angmar in the frigid north still stands and Carn Dûm is now inhabited by nameless things that haunt it’s ancient ruins.
After freeing the hobbits from the evil mound on the Barrow-downs, Tom Bombadil told them of the fallen Kingdom of Arnor and the terrible King who destroyed them.
He chose for himself from the pile a broach set with blue stones, many-shaded like flax-flowers or the wings of blue butterflies. He looked long at it, as if stirred by some memory, shaking his head, and saying at last.
‘Here is a pretty toy for Tom and for his lady! Fair was she who long ago wore this on her shoulder. Goldberry shall wear it now, and we will not forget her!’
For each of the hobbits he chose a dagger, long, leaf-shaped, and keen, of marvelous workmanship, damasked with serpent-forms in red and gold. They gleamed as he drew them from their black sheaths, wrought of some strange metal, light and strong, and set with many fiery stones. Whether by some virtue in the sheaths or because of the spell that lay on the mound, the blades seemed untouched by time, unrusted, sharp, glittering in the sun.
‘Old knives are long enough as swords for hobbit-people,’ he said. ‘Sharp blades are good to have, if Shire-folk go walking, east, south or far away into dark and danger. Then he told them that these blades were forged many long years ago by Men of Westernesse: they were foes of the Dark Lord, but they were overcome by the evil king of Carn Dûm in the Land of Angmar.
From The Lord of the Rings: The Fellowship of the Ring in the chapter ‘Fog on the Barrow-downs’