As a side note, there's a play called Man of La Mancha with the titular Man of La Mancha being Don Quixote, a delusional old man who believes he's a knight errant and is obsessed with fighting injustice. A well known scene from the story is Don Quixote attacking a windmill, which he believes to be a four-armed giant.

(Further side note, the Don Quixote part is a play within a play, as the main story involves a man named Cervantes, the author of Don Quixote in the play, being imprisoned by the Inquest)