Ring-inscription

An inscription in fine lines of fiery Elvish script running around the One Ring, on both its outer and inner surface. The words of the inscription were invisible under normal circumstances, but appeared when the Ring was heated. When worn by Sauron, the inscription seems to have been visible at all times, but Isildur recorded that once removed from the Dark Lord's Black Hand, the writing slowly faded. When the Ring was heated in Bag End millennia after Isildur's time, it was the appearance of the Ring-inscription that finally convinced Gandalf that the Ring found by Bilbo Baggins was indeed Sauron's One Ring.

The words of the inscription are given in Chapter I 2 of The Fellowship of the Ring (The Shadow of the Past). In the original Black Speech, they read Ash nazg durbatulûk, ash nazg gimbatul, ash nazg thrakatulûk agh burzum-ishi krimpatul. Gandalf translated these words as:

Celebrimbor of Eregion bore his own Ring of Power at the time the One Ring was forged by Sauron, and he heard the words of the Ring-inscription at that time, and thus Sauron's scheme to dominate the Elves was revealed. That Celebrimbor was aware of these words suggests that they played a crucial part of the making of the Ring, perhaps even appearing on its band as the Dark Lord spoke them.

The two lines inscribed on the Ring form part of longer rhyme from ancient Elven-lore, telling of the Three Rings of the Elves, the Seven Rings of the Dwarves and the Nine Rings of Men. The lines of this longer rhyme cannot have been part of Sauron's original invocation, because at that time he did not even know of the existence of the Three Rings, nor had he given the Seven or the Nine to Dwarves and Men. Apparently this introductory part of the rhyme must have originated at a later date, designed to fit the two lines uttered at the time of the Ring's forging and inscribed on its band.