Sauron is the first recorded bearer of the One Ring in J.R.R. Tolkien’s Middle-earth chronology.
Sauron secretly forged the One Ring in the fires of Mount Doom during the Second Age. He intended it to control the other Rings of Power and to extend his power over their bearers. Because the One Ring contained much of his own strength, its loss weakened him profoundly.
After Sauron was defeated at the end of the Second Age, Isildur cut the Ring from his hand. Isildur then claimed it, but he was ambushed and killed near the Gladden Fields, where the Ring slipped from his finger and was lost.
Gollum and Frodo are much more familiar later bearers, which can make the chronology confusing. Isildur was the first person to take the Ring from Sauron, but Sauron himself forged it and possessed it first. The question therefore concerns the earliest recorded bearer, not the first human owner.