Sismonda’s substitution trick turns a husband’s discovery of his wife’s secret signal into a domestic reversal: Arriguccio Berlinghieri believes he has caught and punished Madam Sismonda, but the woman he beats is her maid. By the time her brothers arrive to judge the accusation, Madam Sismonda has restored the room, dressed as if she has not gone to bed, and prepared an alternative account that makes her husband appear drunk and unreliable. The trick does more than conceal her affair with Ruberto; it transforms the evidence of the husband’s supposed triumph into the means of his public humiliation and her future freedom.

Background: Marriage, absence, and surveillance

The episode is told by Neifile as one of the Seventh Day’s stories about wives who outwit their husbands. Arriguccio is a wealthy merchant who, in the narrator’s account, has married above his own station in the hope of ennobling himself. His wife, Madam Sismonda, is a young gentlewoman whom the story describes as ill-matched to him. While Arriguccio is often away on business, she falls in love with Ruberto, who has courted her for a long time, and begins a secret affair with him.

The relationship changes when Arriguccio becomes intensely jealous. The story does not establish exactly what first arouses his suspicion; it allows that he may have sensed something or that another cause may have prompted him. Whatever the origin, he abandons much of his ordinary activity to watch his wife. He will not go to sleep until he has felt her get into bed, leaving Madam Sismonda unable to meet Ruberto. His vigilance makes access itself the problem the lovers must solve.

The signal and its discovery

Madam Sismonda devises a concealed signal that uses a length of twine, her bedroom window, and her own toe. One end of the cord hangs from the window toward the street; the other runs across the floor to the bed and is hidden beneath the coverings. Once she is in bed, she ties it to her toe. Ruberto pulls the cord when he arrives at midnight. If Arriguccio is asleep, she releases it and goes to let her lover in; if her husband is still awake, she draws the cord back, telling Ruberto not to wait. The arrangement sometimes succeeds and sometimes does not, but it gives the lovers a way to test the danger without speaking or opening the door prematurely.

One night, while Madam Sismonda is asleep, Arriguccio feels the cord and recognizes that it is attached to her toe. He traces it to the window, quietly cuts it free, ties it to his own toe, and waits. When Ruberto pulls, the knot comes loose in his hand because Arriguccio has not fastened it securely. Ruberto understands that he must wait rather than enter. Arriguccio, meanwhile, gets up armed and runs to the door. He opens it less carefully than his wife would have, and Ruberto recognizes that the person answering is the husband, not Madam Sismonda. He runs; Arriguccio follows, and the two armed men exchange blows after Ruberto turns to defend himself.

The substitution in the bedroom

The noise of the fight rouses the neighborhood. Arriguccio fears that people will recognize him, so he lets Ruberto escape and returns home without having identified or injured him. As he opens the chamber door, Madam Sismonda wakes and sees that the cord has been cut from her toe. She immediately understands that her device has been discovered and that her husband has gone after her lover.

Anticipating what may happen when Arriguccio returns, she calls her maid, who knows about the affair, and persuades her to take her place in bed. The maid is asked to endure whatever blows Arriguccio may deliver without giving herself away; Madam Sismonda promises to reward her. She extinguishes the bedroom light, leaves the room, and hides elsewhere in the house. The substitution depends on darkness, the husband’s anger, and his confidence that the woman in the bed must be his wife.

Arriguccio comes back furious, takes the maid for Madam Sismonda, and beats her with his hands and feet. He also cuts off her hair, continuing to scold her as if she were the guilty wife. Her cries for mercy are broken by sobbing, and his rage prevents him from noticing that her voice is not his wife’s. The beating makes the concealment costly: the maid is badly bruised and has her hair cut, while the real target remains hidden.

Evidence turned against the accuser

After the beating, Arriguccio says he will fetch his wife’s brothers and send her away. Once he has locked the door from outside and left, Madam Sismonda emerges, relights the room, comforts the injured maid, and takes her to another chamber to be cared for. She rewards her from Arriguccio’s own money. She then makes the bed look as if nobody has lain in it and dresses as though she has not yet gone to bed. With a lamp, her clothes, and her sewing, she waits at the head of the stairs.

At her brothers’ home, Arriguccio recounts the cord, the pursuit, and the beating. As proof, he shows them the hair he believes he has cut from his wife’s head. Her three brothers are incensed and set out with torches, intending to deal with her; their mother follows, weeping and urging them not to accept the accusation without seeing their sister or learning more. When the family reaches the house, Madam Sismonda is sitting and sewing. Her face bears no trace of the severe beating Arriguccio claims to have inflicted, and her hair is intact. The discrepancy makes her brothers pause and leaves her husband unable to explain what they see.

Madam Sismonda says she does not know what Arriguccio has complained of and denies that he was at home with her that night. She does not offer the true account of the cord or the maid. Instead, she supplies a plausible fiction: Arriguccio, she says, often spends nights drinking in taverns and consorting with women, then comes home late. He may have mistaken another woman for his wife, beaten her, and confused the incident with his own household. She presents the hair and the alleged beating as evidence not of her adultery but of her husband’s drunkenness. Her mother and brothers accept this explanation more readily than Arriguccio’s story, especially when he cannot produce any mark on Madam Sismonda.

Outcome and narrative significance

The brothers rebuke Arriguccio and warn him not to bring them another accusation of this kind. He leaves bewildered, unsure whether what he experienced truly happened or whether he dreamed it, and says no more about the affair. The story closes by crediting Madam Sismonda’s quick wit with both averting the immediate danger and opening a way for her to pursue her own pleasure without further fear of her husband.

The episode’s reversal rests on a precise chain of material signs: the cord that is meant to announce Ruberto’s arrival exposes the lovers’ arrangement; the loose knot allows Ruberto to escape; the darkness lets the maid take Madam Sismonda’s place; and the cut hair, carried as proof, becomes a false witness when the wife appears uninjured. Arriguccio’s surveillance gives him the appearance of control, but his response to the signal leaves him vulnerable to the substitution. Neifile frames the episode as a comic tale of a wife’s ingenuity against jealousy, while its comedy does not erase the maid’s injury: the successful deception is accomplished partly by transferring the husband’s violence onto another woman.