Origins and early Years Edit
The Elves were content and dwelt long under the stars of the forest near Cuiviénen. However, Melkor, the Dark Lord, became aware of them and their location before the Valar, and during this time he sent evil spirits to spy on them and do them harm. Many of the spirits that harassed the Elves.
Due to Melkor's foresight and malice, some elves were afraid. Hiding and fleeing, some of these early elves were taken by Melkor or his agents. These elves were never seen again and were taken to Utumno, and were believed to be twisted and mutilated until they became the Orcs.
First Age Edit
In the First Age, thousands of Orcs were bred in Angband by Morgoth and to participate in the Battles of Beleriand, which lasted 587 years. They first appeared in the Battle of Lhammoth, where they were defeated by the Noldor. When the House of Fëanor returned to Middle-earth Morgoth sent a force of Orcs against them. Although the Orcs outnumbered the exiles they were no match for the power and wrath of the Ñoldor, and were quickly and easily defeated. However, Fëanor could not defeat the power of Morgoth alone and he was killed, leaving the Orcs to continue to breed under the Dark Lord. Years later, when the House of Fingolfin arrived in Middle-earth, Orcs were sent against them as well, but they were utterly defeated in the Battle of the Lammoth.
After their crushing defeat in the Dagor Aglareb and in a minor raid on Hithlum, the Orcs nevertheless regained their numbers and fought again in large numbers in the Dagor Bragollach and Nirnaeth Arnoediad. They were nearly destroyed in the War of Wrath, and those that survived fled eastwards into the Mountains of Angmar and the Grey Mountains.
Second Age Edit
Sometime around SA 1000, Sauron reappeared in Middle-earth and made the land of Mordor his realm, and then started to build the foundations of Barad-Dûr. During the War of the Elves and Sauron in SA 1700, the Orcs formed the main host of Sauron's power. Despite the immeasurable number of Orcs present, the battle was won by the Elves and the Numenoreans due to their united force and numbers.
Fourth Age and Beyond Edit
Although the entire force of Sauron was extinguished by the end of the War of the Ring, groups of orcs continue to dwell in the Misty Mountains. However, after Durin VII reclaimed Khazad-Dûm, the Dwarves hounded the orcs to near extinction.