The Delphic irony
The plot of the story is a Delphic irony, because a heroic champion-turned-politician consults the Oracle at Delphi which sets off a famous chain of events: every time the Oracle gives a reading of someone's fate, he conceals important aspects of fate, just sharing some parts of it. The shape of his reading makes the character run away from fate, but because of irony, they are actually running headlong into their undesired fate. By cheating on his wife, Basilius precipitates a judgment against himself because his wife literally commits the same sin as him by falling for the same human being. That is only one instance of the irony. Their attempt to escape is obviously futile.
The tragedy of romance
One should think with a subject as fun and interesting as sex and marriage, this book should be kind of upbeat—and it is technically comedic, because it ends with a very humorous and insightful union between Philoclea and Zelmane. The tragedy of romance is ironic in that context, because it underscores the absolute suffering of one's fate. With a sense of humor, everyone will get through this very easily, but without humor, this cast is set up for humiliation and embarrassment around every corner.
Zelmane's irony
Zelmane's irony is perhaps one of the most important in the book. The dramatic irony of Zelmane's character is a subtle commentary on a paradoxical irony within Zelmane's own self. By referring to her as Zelmane, the dramatic irony of identity is retained; secretly, "she" is actually a man, but that does not explain the irony away. Why would a young powerful hero like Pyrocles go straight to a female personality performance in an attempt to woo a young lady? Pyrocles is legitimately feminine at heart, which makes for a highly desirable spouse, it turns out, because he can still fight off predators, but he is sensitive and intimate.
The ironic marriage
The marriage in this novel between Duke Basilius and Gynecia is highly ironic. First of all, their names are literally derivatives of "King and wife," so their relationship is elevated very naturally by their community. Through their ironic marriage, we see what they would never admit to one another. Yes, they are committed, but they still have eyes for other people. Perhaps marriage is designed to constrain natural impulses that never really go away. Most ironic of all—they both betray each other for Zelmane, the sexually confusing androgyne.
The universal fall of man
Musidorous's side plot is interesting and worth of mention here because his dynamic shift from stoic to romantic comes with the full weight of irony. He specifically proves that there is no "out-thinking" one's fate. If one is fated to fall in love by the gods and the prophets, as in this book, there is simply nothing one can do or know that will stop that from happening. Musidorous falls in love while maintaining his eyes-wide-open approach—all his knowledge does not change his biological nature.
