n The Hobbit, written by J.R.R. Tolkien, Elrond was an elf lord who "knew about runes of every kind." Bilbo, Gandalf, and their companion take the map to Elrond to seek his help in reading it. He knows how to decipher the writing, but the dwarf Thorin explains that the runes or 'moon letters' could only be seen when a moon of the same phase and seasons as when they were written shone behind the map.

Based on the letters, Elrond determines the letter were written underneath a crescent moon in mid-summer a long time ago. Elrond translates: "Stand by the grey stone when the thrush knocks," reads Elrond, "and the setting sun with the last light of Durin's Day will shine upon the key-hole."