Less complicated than previous installments, this canto tells a more or less self-contained story about the wronged princess Ginevra. It also has a moral lesson: some guys are just no good. Ariosto opens with a rant against the worst villains of all, men who hurt women:
No creatures on the earth ….This is directed, a little oddly, at the two thugs from whom Rinaldo has rescued Dalinda— oddly since they're not domestic abusers, they're hired assassins, and even wolves are known to kill other wolves they're not married to.
Are hostile to the females of their kind. …
The she-wolf and the wolf at peace appear;
The heifer from the bull has nought to fear. ….
What dreadful plague, what fury of despair
In our tormented bosoms now holds sway,
That wives and husbands constantly we hear
Wounding each other with the things they say? …
An outrage against Nature he commits
Who with his gentle helpmeet stoops to fight,
Or in her face a lovely woman hits ...
Still, Dalinda certainly did have a terrible boyfriend. Hopelessly in love with Duke Polinesso, she's been using Ginevra's room for trysts with him. She describes the affair as a classic teenage disaster, misguided but so very hot:
For many months and days, joys not a fewPolinesso tells her he's going to woo and marry the princess, but it's strictly business; they'll still have their secret love. Dalinda thinks that's just fine. But it's not in the cards anyway, as Ginevra already loves another. Polinesso, who had assumed he was irresistible, decides that if he can't have her then no one can, so he frames her for fornication— by convincing poor Dalinda to dress up as the princess at their next tryst. If this plot sounds familiar, it's because it was reused in Much Ado About Nothing.
We shared; in our delight, no amorous game
Was left untried, and, as our pleasure grew,
I seemed on fire with a consuming flame.
Blinded by love for him, I little knew
How much he feigned …
Dalinda doesn't know the real point of the scheme; he tells her he's developed the hots for Ginevra and wants to role-play his fantasy just this once, so she does it to make him happy. The translator in her notes finds this willingness “not convincing,” but of course it is. Dalinda is a kid in love, they're making up their own rules. Maybe she thinks his fake-princess fetish is a lovable weakness that he was brave enough to admit to her, or maybe she thinks it's kind of fun; it's imaginable either way or both, and Polinesso's choice of such a non-innocent cover story shows him to be a very manipulative guy who understands what'll work with her.
Anyway, the charade works: Ginevra's beau Ariodante goes crazy with jealousy, runs away, and is later seen flinging himself into the sea. His brother Lurcanio accuses Ginevra, and volunteers to prove her guilt in a duel. (Trial by combat was still legal in some places in Ariosto's time, but just barely.) Rinaldo steps up to fight for her innocence, after hearing Dalinda's story— which Polinesso had tried to have her killed to cover up, in case there was any doubt that he is the worst boyfriend in the world.
Rinaldo shows up for the duel, but there's already someone else there to take Ginevra's side: a mystery knight, in generic armor with his face covered. The fight gets under way, but Rinaldo feels bad for Lurcanio (who's after all just a hothead acting on bad information), calls it to a halt, reveals the real story to everyone, and challenges Polinesso. Pretty much everyone in town hates Polinesso and is hoping that he's guilty, but they can't be sure without a duel. It's over soon: impaled on a lance, Polinesso briefly confesses and dies.
That's pretty much it, although there's a passing mention of Ginevra's father the King of Scotland, and her brother Zerbino (somewhere far away), which makes me think they may be important later on. By the way, the king was no help: despite being totally devoted to his daughter, he either couldn't or wouldn't change the anti-nookie law on her behalf— a law that even the monks thought was too prudish. The law isn't mentioned again, so I assume it's still on the books in Scotland to this day. Be careful there.