Isildur's Bane
From Tolkien Gateway
Isildur’s Bane was a name for the One Ring. After Sauron's defeat in the War of the Last Alliance, Isildur, Elendil's son took the Ring, and later journeyed northward with it to his kingdom of Arnor. Ambushed by Orcs, Isildur's small force was cut down, and he fled the battle wearing the Ring. It slipped from his finger, though, and so both Isildur and the Ring were lost.
