War of Wrath
When the Sons of Fëanor went east after Thingol became aware of the Kinslaying, a great fortress was built on the hill of Himring in northeast Beleriand. It was the chief stronghold of Maedhros, from which he guarded the northeastern border region that became known as the March of Maedhros. To the east was Maglor's Gap and Ered Luin; to the west the Pass of Aglon, which Curufin and Celegorm guarded. It was the only fortress to survive the Dagor Bragollach. But in the Battle of Unnumbered Tears the Hill of Himring was taken over by the soldiers of Angband. After the Drowning of Beleriand during the War of Wrath, the peak of Himring (also called "Himling", a typographic error) remained above the waves as an island.