J.R.R. Tolkien > The Silmarillion

Sindarin name for the fourth battle of Beleriand, meaning "Battle of Sudden Flame". It began one winter night about 455 years after the first rising of the sun, when Morgoth suddenly sent rivers of flame from the gates of Angband, consuming everything in their path. This burned away the once-green plain of Ard-Galen between the gates of Thangorodrim and northern Beleriand, turning it into a desolate wasteland, which was afterwards known as Anfauglith, or the Gasping Dust. Behind the flames came armies of orcs led by balrogs, and Glaurung, the first of Morgoth's dragons. The highlands of Dorthonion, the domain of Finrod Felagund's brothers Angrod and Aegnor, were overrun by Morgoth's hordes, and they were lost. Maglor's Gap was also conquered, giving Morgoth an entrance into Beleriand itself.

Maedhros' fortress at Himring held up to the assault, as did Finrod's fortress of Minas Tirith for a time, and Fingolfin's mountain strongholds in the Ered Wethrin, but the siege of Angband was broken at the time, and the sons of Fëanor were scattered. Eventually Sauron came to Minas Tirith and defeated Finrod's brother Orodreth, and under his dominion it became known as Tol-in-Gaurhoth, or Isle of Werewolves. Finrod thus found himself surrounded in that region, cut off from any aid, and would have perished were it not for the timely intervention of Barahir (the father of Beren), and to Barahir and his descendants he pledged eternal loyalty in return for saving his life.

While battles raged the high king of the Noldor Fingolfin, filled with rage and desperation, rode in wrath to the gates of Angband and challenged Morgoth to single combat. The battle raged long and hard, and though Fingolfin wounded Morgoth seven times with wounds that would never heal, Fingolfin was eventually crushed by the Hammer of the Underworld Grond, but his body was rescued by Thorondor the king of the Eagles and brought to a peak in the encircling mountains around Gondolin, where his son Turgon built a tomb. Fingon, his elder son, succeeded the kingship of the Noldor.

War never wholly ceased in Beleriand after that, but the Dagor Bragollach is said to have ended the spring of the following year, when the onslaught was lessened.