Unfortunately, the alliance failed to unite all the free peoples of Beleriand, as the Sindar of Doriath and the Elves of Nargothrond refused to participate, due to the treacherous behavior of Maedhros's brothers Celegorm and Curufin in the affair of Beren and Lúthien. Nevertheless, the coalition assembled was an impressive one, including not only the forces of Maedhros and his brothers, but also that of Fingon, the High King, Húrin's men of Dor-Lómin, the Haladin of Brethil, the Dwarves of Nogrod and Belegost, the Falathrim of Cirdan in the Havens of Eglarest and Brithombar and the men of Bor and Ulfang, newly arrived from the east to serve the sons of Feanor. A small contingent led by Gwindor was also sent by Nargothrond, while the great warriors Mablung and Beleg arrived from Doriath.
Unfortunately, unknown to Maedhros, the sons of Ulfang were disloyal, and they delayed his advance in the east. In the west, Fingon and Hurin waited for the signal from Maedhros, and were cheered by the surprise arrival of the army of Fingon's brother Turgon, King of the hidden city of Gondolin. Fingon's forces continued to wait on Maedhros, but were lured out onto the Anfauglith when Morgoth's troops taunted the Noldor by murdering Gwindor's brother Gelmir, a captive in Angband since the Dagor Bragollach, before Gwindor's eyes. Gwindor and his troops rode across the plains, and Fingon was forced to call a general advance. Gwindor's men broke down the first gate of Angband, but were soon surrounded, and Gwindor himself was taken captive. The rest of Fingon's army seemed to be in dire straits until Maedhros's army finally arrived. For a time, the tide of battle seemed to turn. The Dwarves were able to turn back the dragon Glaurung. But the treachery of the men of Ulfang was ultimately the undoing of the opponents of Morgoth. Maedhros's army was largely destroyed, and the sons of Fëanor limped back to Beleriand. The western army was not so lucky. The High King himself was slain by the Balrog Gothmog. Húrin and his brother Huor sacrificed themselves to allow Turgon, now High King, to escape back to Gondolin, conducting a valiant last ditch defense in the Fens of Serech, in which Huor was killed and Húrin captured.
See also: The Silmarillion