Don Quixote is a novel by Miguel Cervantes, fully titled “The Ingenious Nobleman Sir Quixote of La Mancha” or “El Ingenioso Hidalgo Don Quijote de la Mancha.” It is considered the most influential work of literature from the Spanish Golden Age and the entire Spanish literary canon.

“The story follows the adventures of a noble … named Alonso Quixano who reads so many chivalric romances that he loses his sanity and decides to set out to revive chivalry, undo wrongs, and bring justice to the world, under the name Don Quixote de la Mancha. He recruits a simple farmer, Sancho Panza, as his squire, who often employs a unique, earthy wit in dealing with Don Quixote’s rhetorical orations on antiquated knighthood. Don Quixote, in the first part of the book, does not see the world for what it is and prefers to imagine that he is living out a knightly story…The novel is considered a satire of orthodoxy, veracity and even nationalism. ”
- Wikipedia

The song is likely a play on the storyline of the novel from which it takes its name, though the introduction of Gavlyn’s verse does not fit neatly into this interpretation.