War of the Powers

After Oromë discovered the newly awakened Elves, the Valar resolved to remove the threat of Melkor from Middle-earth. They went to war, meeting the forces of Melkor in the northwest of Middle-earth, where the battle that took place left the land scarred and broken. The Valar were victorious, pursuing the fleeing armies of Melkor to his vast stronghold of Utumno, which they besieged. Meanwhile they placed a guard on the Elves at Cuiviénen while the dreadful war continued in the North.

At last the Valar broke the defences of Utumno. Tulkas wrestled with Melkor and defeated him, and the Dark Lord was chained with a great chain made by Aulë, known as Angainor. Melkor was removed to Valinor and imprisoned within the Halls of Mandos for three ages, and Middle-earth had peace for that time. Many of the deep pits and dungeons of Utumno and its outlier fortress of Angband remained, however, and so many of Melkor's servants escaped the destruction. Among these was Sauron, who would prepare Angband for his master's return, many long centuries later.