The style of The Fellowship of the Ring is marked by Tolkien's extensive use of songs, poems, journals, letters, and other musical and textual elements. As a philologist, or a scholar of language in historical sources, Tolkien had a lifelong professional interest in ancient poetry and verse, particularly in Old Norse, Old English, and Middle English. Throughout the novel, characters often break out into song and recite poetry, and their songs and poems frequently reference the fictional history and mythology of Middle-Earth.
In a letter from Gandalf to Frodo, for example, which Frodo receives from Butterbur the innkeeper in Bree, Gandalf ends the letter with a poem:
All that is gold does not glitter,
Not all those who wander are lost;
The old that is strong does not wither,
Deep roots are not reached by the frost.
From the ashes a fire shall be woken,
A light from the shadows shall spring;
Renewed shall be blade that was broken,
The crownless again shall be king.
In these famous lines from the novel, Gandalf sends a cryptic message to Frodo that the hobbit, at first, struggles to understand. The lines, in fact, refer to Aragorn, whom Frodo knows as Strider, and they contribute to the reader's understanding of the vast, fictional history of Tolkien's setting. Just as "all that is gold does not glitter," so too is Strider a valiant and honorable man despite his haggard and intimidating appearance. Other lines in the poem suggest, indirectly, that Aragorn's noble bloodline will be restored and that he "shall be king." Similarly, a line describing a "broken blade" refers to Andúril, a weapon that Aragorn has inherited. Like many other poems and songs in the novel, then, this poem foreshadows later events and contributes to the impression of vast history and mythology in Middle-Earth.