Means? You mean Men? Actually, Sauron was known in the First Age as a lieutenant of Melkor. He had his own stronghold in Tol-in-Gaurhoth (the Isle of Werewolves) and was known as the Lord of Werewolves. The fortress was brought down by the power of Lúthien.
Because the Wise did know of Sauron, he approached them in the Second Age in the disguise of Annatar to gain their trust.