The War of the Valar against Melkor, who was threatening the well-being of the newly awakened Elves. Their first battle was for the newly-built Angband, then the Valar went on to Utumno, which was also broken. Melkor was taken back to Valinor as a prisoner, and was imprisoned in the Halls of Mandos for three ages.

The Elves later remembered nothing of the battle that was fought on their behalf.
Encyclopedia entry originally written by atalante_star