Battle of Fornost
After the fall of Arnor, Círdan summoned all who would come to him, from Lindon or Arnor, and when all was ready the host crossed the Lune and marched north to challenge the Witch-king of Angmar, who then dwelt in Fornost.The Witch-king had filled Fornost with evil folk, usurping the house and rule of the kings.
There was a great battle on the plain between Nenuial and the NorthDowns. The forces of Angmar were already giving way and retreating towards Fornost when they were scattered by the main body of horsemen coming from the north. The Witch-king tried to gather all he could from the wreck of his army and flee northwards to his own land of Angmar, but before he could gain the shelter of Carn Dûm the cavalry of Gondor overtook him with Eärnur riding at their head. At the same time a force under Glorfindel the Elf-lord came up out of Rivendell. Then so utterly was Angmar defeated that not a man nor an orc of that realm remained west of the Mountains.
When all was lost, the Witch-king himself appeared, black-robed and black-masked upon a black horse. Fear fell upon all who beheld him; but he singeled out the Captain of Gondor for the fullness of his hatred, and with a terrible cry he rode straight upon him. Eärnur would have withstood him, but his horse could not endure that onset, and it swerved and bore him far away before he could master it. Then Glorfindel rode up on his white horse, and in the midst of his laughter the Witch-king turned to flight and passed into the shadows, and none saw wither he went. Eärnur rode back, but Glorfindel looking into the gathering dark, said: "Do not pursue him! He will not return to this land. Far off yet is his doom, and not by the hand of man will he fall."
So ended the evil realm of Angmar, and so did Eärnur earn the chief hatred of the Witch-king.