The Second Age
This period lasted nearly three and a quarter thousand years and set the stage for much of the information in The Lord of the Rings and The Hobbit. It is also the setting for Amazons' upcoming series. Even though Morgoth was killed in the War of Wrath the dark forces remained in hiding, eager to continue their quest against Eru Ilvatar and the Valar. The Second Age is a period of relative peace for Arda. The Elves start slowly emigrating westwards to establish themselves on Middle-Earths shores. But it wasn't to be. About halfway through the Second Age, Sauron (one of Morgoths chief lieutenants) begins to plot his schemes to corrupt both the Elves and Men.
Sauron, disguised as the Maiar Annatar ensorcells Elves of Eregion to create the ring power. He also forges the One Ring to rule all who use it. After the discovery of Saurons deception, a war breaks out between Sauron's Elves and Middle-Earth's Elves. This leads to the defeat of the second Dark Lord. However, centuries later, the Nmenorean King Ar–Pharaznhead, a Kingdom that had grown beyond Nmenor, marched an army into Mordor in order to capture Sauron. He was then imprisoned on Nmenor. Sauron soon began to corrupt the Nmenoreans and turned them against the Valar, convincing Ar-Pharazn that he would attempt to land on Aman to attack the Valar. It's a very bizarre move: Eru Ilvatar appears and is so mad that he not only destroys the Nmenoreans, Saurons physical form, but also sinks Nmenor completely and cuts Aman off from the rest of Arda. How is this possible? He makes Arda a spherical, rather than flat, planet after a long time and many thousands and thousands of years.
The Nmenoreans who remain flee to Middle-Earth establish the kingdoms Gondor or Arnor. After a few hundred years, Sauron rebuilds his physical form. Because it is how Fellowship of the Ring opens, you know what happens next: the Last Alliance of Elves and Men forged to defeat Sauron. It culminates in his body being destroyed by Prince Isildur on the steps of Mount Doom.
