The War of Wrath was the great battle that ended the First Age in Tolkien’s mythology.
The conflict was fought between the forces of the Valar and the hosts of Morgoth, the first Dark Lord. The Valar intervened after Eärendil reached Valinor and pleaded for help on behalf of Elves and Men. Their armies entered Beleriand, joined by the Vanyar and many other allies, and confronted Morgoth’s power in the final stage of the long wars over the Silmarils.
The battle lasted for more than 40 years according to Tolkien’s chronology. Eärendil, traveling in the sky aboard Vingilótë, killed Ancalagon the Black, the greatest of Morgoth’s winged dragons. The devastation was so immense that much of Beleriand was broken and submerged beneath the sea.
The War of Wrath is sometimes confused with the War of the Ring, which occurs in the Third Age, or the Battle of the Last Alliance, which ends the Second Age. Its defining setting is the First Age and the fall of Morgoth.