The writing system on the One Ring in J.R.R. Tolkien’s The Lord of the Rings is Tengwar.
The Ring inscription is written in Tengwar, a script devised by the Elf Fëanor. The letters appear as elegant flowing characters around the Ring. The inscription itself uses the Black Speech of Mordor, not an Elvish language, which is why the script and the language must be distinguished.
Its English translation is: “One Ring to rule them all, One Ring to find them, One Ring to bring them all and in the darkness bind them.” The verse comes from the longer rhyme describing the Rings of Power.
Readers often confuse Tengwar with Cirth. Cirth is another writing system associated with Tolkien’s world, originally developed by the Sindar and later used by the Dwarves. The Ring’s inscription is specifically Tengwar lettering. Tolkien also used Tengwar to write many real-world languages and invented languages in his notes and illustrations.