Dagor Aglareb

Seeking to catch the Elves unprepared, a twin force of Orcs marches from Angband to attack Beleriand from both the west and the east.

(1)	In the west, the Orcs break through the Pass of Sirion.
(2)	In the east, they pass through the low hills of Maglor's Gap. Both of the elements of this dual force make for the land of Dorthonion.
(3)	Fingolfin leads a force from Barad Eithel and drives into the western Orcs.
(4)	Maedhros attacks the flanks of the eastern Orcs from his fortress on Himring.
(5)	Orcs from both armies flee back to Angband, with the forces of Fingolfin and Maedhros pursuing them across the plain of Ard-galen.

As the years drew on after the Return of the Noldor to Middle-earth, the newly returned Elves seemed content to leave Morgoth quiet in Angband, setting no siege and attempting no direct attack. Concluding that his enemies were unprepared for war, Morgoth resolved to launch a sudden assault of his own: Orcs by the thousand marched south from Angband's gates, while the earth shook and the Iron Mountains burst into flame.

It seems that Morgoth's strategy was to capture Dorthonion, the highland region held at that time by Finarfin's sons Angrod and Aegnor, which blocked direct access to Beleriand from the north. His Orcs formed two main armies: one travelling down the Pass of Sirion to the west of Dorthonion, and the other through Maglor's Gap to the east. While skirmishing parties broke off and headed further south, the two main armies started an assault on Dorthonion itself from both the west and the east.

Morgoth's spies had failed him, and the Noldor were more alert than he had imagined. In the west Fingolfin led his army against the Orcs, while in the east Maedhros did the same. The few Orcs that survived fled back towards Angband, but the Eldar slew them all among the grasslands of Ard-galen, and not a single Orc returned to Angband.

This was one of the greatest victories of the Elves over Morgoth, and it became known as the Glorious Battle, or Dagor Aglareb. It also served as a warning, and the Eldar redoubled their defences against Angband. After the Dagor Aglareb, they set the great Siege of Angband, and the people of Beleriand were kept safe from any major attack until the time of the Dagor Bragollach, nearly four centuries later.