Act 3 opens in Rome, as Francisco and Monticelso prepare Vittoria's trial for the murder of Camillo. As their Chancellor and Register physically set the stage for the trial, Francisco and Monticelso discuss how they will blacken Vittoria's name, despite their lack of concrete evidence.
The four men soon leave, and Flamineo, Marcello, and a Lawyer enter. The lawyer chides the two brothers, explaining that Vittoria will be easily convicted if any evidence exists showing she has even kissed Brachiano. Flamineo jokes with the lawyer, twisting his words around to make sexual innuendos in order to prevent suspicion of his own guilt in the matter. Marcello, however, is in a miserable mood, and chastises his brother for helping Brachiano and Vittoria enact their illicit schemes. Flamineo counters that his goal was always to better his and Vittoria's fortunes. He criticizes Marcello for serving Francisco for very little money, but Marcello interrupts and insults him.
At that moment, several foreign ambassadors, who are to judge the trial, walk across the stage. The Savoy Ambassador enters first, followed by the French Ambassador. The Lawyer and Flamineo mockingly discuss the French Ambassador's talent for tilting, which is also a pun for sexual intercourse, and Flamineo further describes him as impotent. The England and Spanish Ambassadors arrive last, and Flamineo insults them to himself. Everyone exits.
Scene 2 presents Vittoria's arraignment. It begins as Francisco, Monticelso, the Ambassadors, Brachiano, Vittoria, Zanche, Flamineo, Marcello, the Lawyer, and a guard file in.
Monticelso explains to Brachiano that there is no chair for him, so Brachiano lays a rich gown underneath himself as a place to rest. Monticelso then calls Vittoria and Zanche to the stand, and the lawyer enters a plea against them in Latin. Vittoria asks for the lawyer to speak in his "usual tongue" so that the spectators can understand. She believes that Latin will cloud the trial and judgment. Francisco grants the request, so the lawyer, searching for large, Latin-esque words, delivers a flowery, nonsensical rant against Vittoria. Vittoria protests, and Francisco dismisses the lawyer.
Monticelso now takes control of the prosecution, accusing Vittoria of being a whore. When Vittoria asks him to elucidate his meaning, he compares whores alternately to poisoned perfumes, Russian winters, high taxes, and counterfeit money. When Vittoria denies the charge, the ambassadors discuss the case, concluding that she has lived "ill," but that Monticelso is also "too bitter" to be trusted as impartial. Together, Francisco and Monticelso present the case claiming that Vittoria killed Camillo. In her defense, Vittoria kneels before the ambassadors and begs forgiveness for her strong, masculine assertions and personality. The ambassadors are impressed by her bravery, and Vittoria triumphantly tells Monticelso that the insults he used towards her are easily leveled back at him.
To further implicate Vittoria, Monticelso asks her who was in her home the night her husband was murdered. Brachiano stands up and admits to being there, but claims that he was trying to help Camillo settle his debt to Monticelso. When Monticelso accuses Brachiano of indulging his lust, Brachiano insults Monticelso and leaves the courtroom, leaving his rich coat behind. Francisco asserts that the prosecution lacks sufficient evidence to convict Vittoria, and moreover believes her soul is not "black" enough to commit such a deed.
In answer, Monticelso produces a letter from Brachiano to Vittoria, which entreats her to join him at a summer-house. Vittoria reminds him that they have only his invitation and not her "frosty" response to it, and so the letter proves only his lust, and not her sin. Vittoria claims she has only committed petty sins, and that Monticelso is accusing her unsympathetically and unfairly.
Monticelso next reveals that Brachiano gave Vittoria money, which she claims was meant to pay her husband's debt. She insists Monticelso cannot fairly act as both prosecutor and impartial judge, and appeals to both the ambassadors and the audience for judgment instead. Monticelso then tells the story of Camillo's marriage to Vittoria, claiming Camillo received no money from her dowry, and that she had always acted like a whore.
Monticelso prepares to pass judgment. He first tells Flamineo and Marcello that they must stay nearby even though he does not yet have evidence with which to charge them of a crime. He then sentences Vittoria to a "house of convertites," a home for penitent prostitutes. Vittoria screams for vengeance and insists Monticelso has raped Justice as she is led away.
Brachiano enters, dazed and upset. He says a few mysterious and mournful words to Francisco before leaving again. Aside, Flamineo congratulates Brachiano on his performance, and resolves to also act like he is mad with grief other Vittoria's punishment so that nobody will think him guilty of anything.
He exits, and Lodovico and Giovanni enter together. Dressed in black, Giovanni reveals to his uncle that Isabella is dead. The ambassadors leave the stage at Monticelso's request, and Giovanni mourns his mother's death, asking Francisco what happens to the dead. Deeply upset, Francisco sends Giovanni and Lodovico away so that he may mourn Isabella's death privately.
Flamineo enters, acting distracted and insane as planned in the previous scene. When Marcello and Lodovico follow him, Flamineo gripes about his misfortune, listing all the situations he'd prefer to serving Brachiano. The Savoy Ambassador enters and tries to console Flamineo, but he rebuffs the condolences. The French Ambassador then enters and argues that the proof of guilt was clear, but Flamineo accuses Monticelso of being corrupt and using bribes. The English Ambassador enters and Flamineo continues cursing at Monticelso.
All three ambassadors leave, and Flamineo subtly insults Marcello, partly by referencing Cain's murder of Abel. Flamineo then leaves the stage. Aside, Lodovico comments on Flamineo's scandalous words, and resolves to learn more of the man. Flamineo re-enters, wondering how and why Lodovico is back, since he is still officially banished. The two men exchange subtle insults.
Gasparo and Antonelli enter, laughing. Flamineo refers sarcastically to the "grieving" couple, while he and Lodovico exchange a few more insults and then make a pact to stop arguing. Antonelli tells Lodovico that the Pope, on his deathbed, has signed Lodovico's pardon. Rejoicing in his good fortune, Lodovico breaks with Flamineo and calls Vittoria a whore. Flamineo strikes Lodovico, and Marcello drags him away. Lodovico is upset to have been hit by Flamineo, whom he considers a low-class pimp. Nonetheless, he resolves to forget the insult and get drunk instead.
Act 3 is the center of the narrative action. Most of the act, which is divided into smaller scenes mostly for convenience and could be performed as a continuous scene, is concerned with Vittoria's trial. This central event allows Webster to explore and express most of his play's major themes in an explicit fashion, and it also showcases how deeply Webster's pessimism runs.
A woman's lack of agency is quite clear in the trial, both through the story and through the theatricality. One interesting aspect is how the trial deepens Vittoria's character, and explores her as more than just a lover or sensual figure. She demonstrates intelligence and power by commanding that her lawyer not speak in Latin. She wants the trial to be clear for everyone, and although she knows Latin (a rare accomplishment for a woman in that period), she fears the esoteric language will alienate those to whom she might appeal for justice. Unfortunately, though her clever use of power does get the Lawyer eliminated, Cardinal Monticelsco quickly seizes what power she has.
One other way that the trial explores a woman's position is through an interesting theatrical device. In describing the stage, Webster writes that Isabella is amongst those watching, even though she died in the previous act. While this could be simply a slip-up, it is also possible that Isabella and Zanche were meant to be played by the same actress. This casting would connect the two women in the audience's minds, and thereby connect Isabella and Vittoria. Although they are often presented as polar opposites, one being a whore and the other a martyr, it is also possible to argue that their similarities as women are more significant those those differences. Each woman has a complex mix of vice and virtue within her, and both women are ultimately victims of male desires and social forces.
The most overpowering impression left by the trial is the intense misogyny that is personified through Monticelso. Though he admits that he has no concrete proof, he energetically seeks conviction solely on arguments that attack her character, focusing on her misuse of female sexuality. Vittoria has many logical arguments - she says one cannot blame a river for a man's suicide, for instance - but as she notes, a woman can only find revenge through words whereas men can exploit fears of cuckoldry or contempt for overly-sexualized women as tools. When she apologizes to the judges for having appeared too masculine, it is a last ditch effort to acknowledge why she is being persecuted and then hopefully help them transcend their prejudices.
And of course, the trial reveals a blatant misuse of power. Monticelso's conflict of interest as both prosecutor and judge underscores how corrupt the system is, and how difficult it is to rise above it. Monticelso and other "great men" like him guard the gate to freedom and social betterment, preventing not just a woman like Vittoria, but also a poor man like Flamineo, from achieving what they desire. Monticelso's pretension to an unbiased opinion is most dangerous of all, since it guards him from legitimately reforming. As a result, the system itself is somewhat to blame for inspiring cruelty and crime in the likes of Flamineo, who merely take what path is available to achieve what they feel capable of.
And yet, the most pessimistic irony of all is that for all this misuse and perversion of power, Vittoria is arguably guilty of having facilitated the crime, as the audience knows from earlier. Further, she did so through a clever ruse that stroked Brachiano's ego, through the very type of intrigue that frightens men like Monticelso.
At the end of Act 3, another parallel occurs in the meeting of Lodovico and Flamineo. Both men could be considered the base villains of the play - they are the primary murderers, they both toe the line between knave and gentility, and they both unhappily work for "great men." Their meeting provides the audience with cue to follow their story, to see how their paths deviate.
Finally, Webster uses an interesting device when Lodovico notes that "Fortune's wheel" has spun in his favor. This allusion to Fortune's wheel evokes a torture wheel which, to men of their position, also applies. Misfortune can be tantamount to torture, and Lodovico may, by the end of the play, undergo actual torture for his part in the murders.