In the earliest of days, before the Valar entered Arda, Sauron was originally known as Mairon the Admirable, a powerful Maia of Aule the Smith, a Vala. However, Mairon was soon corrupted by the Dark Lord Morgoth an evil Vala and Dark Enemy of Arda, and turned evil, taking the name, “Sauron.” At first, he was a spy for Morgoth, telling him the Valar’s doings.
“Hador Lórindol, son of Hathol, son of Magor, son of Malach Aradan, entered the household of Fingolfin in his youth, and was loved by the King. Fingolfin therefore gave to him the lordship of Dor-lómin, and into that land he gathered most of the people of his kin, and became the mightiest of the chieftains of the Edain. In his house only the Elven-tongue was spoken; but their own speech was not forgotten, and from it came the common tongue of Númenor.”
Lord of the Rings behind the scenes: Warriors of the Third Age - YouTube PLEASE at least watch the bits with World Swordmaster Bob Anderson, starting around 5min. They don't call him a master for nothing, he designed the swordfights here AND for Princess Bride, and was stand-in for Errol Flynn.
"Eldest, that's what I am... Tom remembers the first raindrop and the first acorn... He knew the dark under the stars when it was fearless - before the Dark Lord came from Outside." —Tom Bombadil by Alan Lee
“Few ever changed [Fëanor’s] courses by counsel, none by force. He became of all the Noldor, then or after, the most subtle in mind and the most skilled in hand.” ~ The Silmarillion, Of Fëanor and the Unchaining of Melkor. (Artwork: Fëanor Curufinwë by koyak)