After the War of Wrath, Morgoth was defeated and judged by the Valar, but his lieutenant Sauron escaped judgment. The Edain had been offered the isle of Elenna and flourished there. While the Elves and the Dwarves retreated in their respective realms, outside them, "Middle-earth went backward and light and wisdom faded".
The Middle Men who did not heed the summons of the Valar and Morgoth fell back in a primitive state, having no contact with the Eldar or the Edain. Instead, some of the evil Men who escaped the destruction of Beleriand came to the east and became their Kings. For this the Middle Men were neglected by the Valar.
Around S.A. 600 the Númenóreans sent ships to Middle-earth and established contact with the Middle Men and started teaching them agriculture, stonecraft and smithying. But it was around S.A. 882 when King Gil-galad warned the Númenóreans that an evil power was taking shape in the East.
Indeed, Sauron was ever at work corrupting men in the east and the south and established himself to Mordor around S.A. 1000. He fortified the land with the Black Gate and armies of the Men of Darkness whom he corrupted and enslaved. He also built Barad-dûr near Mount Doom.
Sauron attempted to corrupt the prosperous Elves of Eregion persuading them to create the Rings of Power. When the Elves rejected him, they fought a bloody conflict against him, but Sauron destroyed Eregion and devastated much of Eriador, pushing the Elves back to the Blue Mountains, as the Dwarves retreated to Moria.
 The Dark Years begin
Sauron now dominated most of the East and the South, even much of the Westlands and allowing not any freedom or rivalry, he desired to destroy the Elves as well as Númenor. He gathered all evil things of his former master, multiplying the Orcs; he ruled with force and fear but also wore a fair and wise guise to those Men who worshipped him as "Lord of the Earth". It was then when he started to be known as the Dark Lord and the Enemy by those who saw his power spreadng over the world. He started to hunt the Elves who fled to Lindon, where Sauron could not enter, and thence over the Sea to the Uttermost West. Other peoples retreated to the mountains or the woods, in fear.
But then the powerful Númenóreans responded to the Elves' plea and sent ships and armies to their support. The alliance, after heavy fighting, managed to reclaim Eriador and pushed the Dark Lord back to Mordor with a handful of orcs.
 Shadow over Númenor
Meanwhile Númenor fell under the Shadow and the colonists started to oppress the primitive Men of the Westlands, demanding tribute of goods and wealth. Some indigenous folk of Middle-earth were afraid of those Black Númenóreans and their ships who intended at some point to conquer the land of Agar and slay its people.
At some time during the Dark Years, some of the Men of the White Mountains feared Sauron and started worshipping him. Others of their folk migrated northward to the southern dales of the Misty Mountains.
Sauron turned his attention to the west once more, declaring himself "King of Men", starting against the Númenórean colonists and their ports. The arrogant Númenóreans, who were traditionally the "Kings of Men", saw him as their competitor, and once more came against him. King Ar-Pharazôn took Sauron as a captive to Númenor, further corrupting the Númenóreans, who continued to enslave the primitive Men and even using them as human sacrifices. The corruption eventually resulted to the Downfall of Númenor.
Sauron's spirit escaped to Middle-earth, and returned to Mordor, where he slowly rebuilt his strength. Unable to assume a fair shape, he started to rule through terror and force.
 Fall of Sauron
The Faithful who escaped founded Gondor and Arnor in Middle-earth and gathered Mannish peoples under them, including the Men of the Mountains who formerly worshipped Sauron. Sauron still considered the Númenóreans his most hated enemies and he launched a pre-emptive attack against them. The Númenóreans formed a Last Alliance with the Elves of Lindon and fought Sauron in the War of the Last Alliance, where finally Sauron perished.
Sauron's defeat ended the Dark Years and the Second Age, and allowed the Númenórean realms to flourish during the Third Age.
At one point Aragorn mentions the Accursed Years to the Oathbreakers, which Robert Foster identifies as another name of that period. On the other hand, the Encyclopedia of Arda considers it a "term of uncertain meaning", probably referring to the Third Age when the Oathbreakers were cursed to roam the White Mountains.
 Portrayal in adaptations
- Some of the Dark Years are seen during the Prologue to the film accompanied by Galadriel's narration. After Sauron forged the One Ring, his power is seen expanding over a map of the Westlands, with flashback scenes of battles and peoples being ravaged and enslaved by Orcs. The Last Alliance is formed by the Free peoples as a direct response to Sauron's brutalities.
- ↑ 1.0 1.1 1.2 1.3 J.R.R. Tolkien, Christopher Tolkien (ed.), The Silmarillion, "Akallabêth: The Downfall of Númenor"
- ↑ J.R.R. Tolkien, The Lord of the Rings, The Two Towers, "Treebeard"
- ↑ J.R.R. Tolkien, Christopher Tolkien (ed.), Unfinished Tales, "Aldarion and Erendis: The Mariner's Wife"
- ↑ J.R.R. Tolkien, The Lord of the Rings, Appendix A, "The Númenorean Kings", "Númenor"
- ↑ 5.0 5.1 5.2 5.3 5.4 J.R.R. Tolkien, Christopher Tolkien (ed.), The Silmarillion, "Of the Rings of Power and the Third Age"
- ↑ J.R.R. Tolkien, Christopher Tolkien (ed.), The Peoples of Middle-earth, "Of Dwarves and Men"
- ↑ J.R.R. Tolkien, Christopher Tolkien (ed.), Unfinished Tales, "The History of Galadriel and Celeborn", "Amroth and Nimrodel"
- ↑ J.R.R. Tolkien, Christopher Tolkien (ed.), The Peoples of Middle-earth, "Tal-Elmar"
- ↑ J.R.R. Tolkien, The Lord of the Rings, Appendix F, "The Languages and Peoples of the Third Age", "Of Men"
- ↑ 11.0 11.1 Robert Foster, The Complete Guide to Middle-earth, p. 82
- ↑ Mark Fisher, "Accursed Years: The long years of Isildur's curse", Encyclopedia of Arda (accessed 19 May 2012)