The One Ring is the gold ring forged by Sauron and central to J.R.R. Tolkien’s The Lord of the Rings.
Sauron created the Ring in the fires of Mount Doom during the Second Age, putting a large part of his power into it. Its purpose was to dominate the other Rings of Power and control their bearers. The Ring’s inscription, written in the Black Speech, reveals its connection to the ruling power of its maker.
Isildur cut the Ring from Sauron’s hand after the battle of the Last Alliance, but he did not destroy it. It later passed through the hands of Déagol, Sméagol and Bilbo Baggins before Bilbo gave it to Frodo. The quest of the narrative is to carry it back to Mount Doom and destroy it.
The One Ring is sometimes confused with the Silmarils, which are jewels from the First Age, or with Narsil, the sword that cut the Ring from Sauron.