Fourth Battle of Beleriand (455 Y.S.) - Also known as Dagor Bragollach (The Battle of Sudden Flame).  After Dagor Aglareb, the Elves laid siege to Angband to prevent another attack.  It lasted four-hundred years.  Morgoth finally broke the siege with Dagor Bragollach.  Fingolfin was killed by Morgoth when he challenged him to single-combat.

"Thus ended the Siege of Angband; and the foes of Morgoth were scattered and sundered one from another.  The most part of the Grey-elves fled south and forsook the northern war..." ~The Silmarillion, chap. 18 (On the Ruin of Beleriand)