At the start of the thirtieth canto, Dante waxes lyrical with mythological examples on the theme of anger, alluding to the story of Jupiter and Semele. Jupiter lusted for her, which invariably evoked Juno’s rage, and she subsequently exacted her rage by driving Athamas, Semele’s brother-in-law, into a violent frenzy and causing him to murder his own child; after learning of this horrifying act, his wife—Semele’s sister—took her and her other child’s lives out of sorrow. 

As he ponders this story, he recalls another and recounts the tragic tale of Hecuba. As the Queen of Troy, she witnessed her daughter's murder, discovered her son's lifeless body by the shore, and suffered from insanity while in Greek captivity. 

These acts of violent emotion, he notes, pale in comparison to the fervent fury he observes in the Eighth Circle. Capocchio accompanies Dante through this realm, identifying the spirits who dwell there. He points out Gianni Schicchi, an impersonator and forger, as well as Myrrha, yet another deceiver who disguised herself in order to commit a dishonorable deed with her father. 

Dante encounters a spirit suffering from dropsy—a term indicating painful swelling—and bloating. This spirit introduces himself as Master Adam, who had counterfeited coins in Romena that depicted John the Baptist. Adam blames Guido, Alexander, and their brother, all counts in Romena, for coercing him into committing the fraudulent act and takes no responsibility for the crimes that landed him here.

Dante inquires about the nearby spirits; Adam explains that one is Sinon, the Greek soldier who lied to the Trojans about the nature of the Trojan Horse, and the other is a Potiphar’s wife, who falsely accused the biblical Joseph of assault.  

As Adam names the shades, Sinon approaches, and the pair break into a heated argument. Dante stares on in amazement, but Virgil soon urges him along, demanding he stop staring or else they will quarrel. Dante is embarrassed by the chastisement, but Virgil reassures him, explaining that it is not a significant issue and kindly advising him that it is impolite to observe such a spectacle.