Two gentlemen of Cymbeline’s royal court lament the sad state of current affairs. Though most act as if the King’s anger is justified by frowning themselves, most are in agreement that the King’s daughter, Imogen, did right to oppose the King by choosing Posthumus over Cloten. Their talk informs us that Posthumus is the son of a great warrior whose service to Britain warranted the King adopting the parentless Posthumus as a in-house servant. As for Cloten, he is the son of the Queen by a previous marriage and is accounted unworthy--so unworthy that the Queen herself advocates Imogen’s choice of Posthumus at the expense of her own son (or so she gives the impression). Presently, the two gentlemen give way as the scene is taken over by the Queen who promises Imogen and Posthumus that she will do what she can to have the King see them as a legitimate couple. Meanwhile, she advises them to do as the King commands and separate. And so Imogen and Posthumus say their goodbyes, exchanging a ring and a bracelet as tokens of their love when Cymbeline emerges. He drives away Posthumus and urges the Queen to keep Imogen grounded and sequestered. Shortly after the King’s departure, Posthumus’ servant, Pisanio, appears. He tells Imogen that he will act as go-between between Posthumus and her during Posthumus’ exile.
When Posthumus was on his way to serve his exile, Cloten had assaulted him, and though nothing had come of it (Posthumus had merely parried Cloten’s sword thrusts and had made an easy escape) Cloten boasts of it to his attending lords. Lord #1 flatters Cloten, saying how he had soundly beaten Posthumus, while Lord #2 disparages Cloten with remarks off to the side.
As Pisanio was present when Posthumus sailed off for Italy, Imogen plies Pisanio with questions as to Posthumus’ final words and gestures. Pisanio’s replies persuades Imogen that Posthumus’ final thoughts were fixed on her and only her. Nonetheless, she laments their final goodbyes which were hastened by her father, causing her to leave out much of what she had wanted to say.
Posthumus arrives in Rome, Italy where he is greeted by Philario and some of Philario’s friends. Among Philario’s friend is Jachimo a man who isn’t overly impressed with what is generally known to be Posthumus‘ story. Another is a Frenchman who is personally acquainted with Posthumus and who holds a high regard for him. The Frenchman and Posthumus share their memories of a silly dispute that had occurred in France which dispute Jachimo rekindles by provoking Posthumus into reliving it. Jachimo asserts that no woman, including Posthumus’ beloved Imogen, is so incorruptible these days as to be able to resist his charms. He is so sure of it that he is willing to stake his wealth on it. Posthumus agrees to accept the wager (he will stake the gold ring that was given him by Imogen), but he adds that if Imogen proves to be incorruptibly chaste that Jachimo will have to answer with his sword for slandering Imogen, never mind his wealth.
When Cornelius asks the Queen why she has requisitioned a supply of various poison, she replies that the physician should have no reason to be concerned as she will use them to contrive various fragrances in the manner taught by Cornelius himself, and as she will test them on lowly creatures to see if she can contrive an antidote to their effects. Not believing a word of this, Cornelius supplies the Queen with powerful sedatives. By and by, the Queen makes a gift of what she believes to be poison to Pisanio, promising him rewards that would enlarge his status to a degree even greater than Posthumus’ if he succeeds in persuading Imogen to forget about Posthumus and to love Cloten. But Pisanio resolves to remain true to Posthumus.
Upon being introduced to Imogen, Jachimo assures Imogen that her husband, Posthumus, is doing very well. In fact he’s doing so well, Jachimo says, that Posthumus not only makes a sport of mocking a Frenchman for pining for his lady, arguing that no woman deserves such devotion as no woman is ever faithful to her husband, but that he spends his time cavorting with prostitutes. Imogen doesn’t know what to make of all this but she knows that she doesn’t want to hear anymore. She begs him to stop, but he persists, telling her how she could get her revenge on her husband by sleeping with him--Jachimo. Outraged, she accuses him of slandering her husband and promises Jachimo that her father will be informed of his vulgar advances. Cleverly, Jachimo changes his tactic, arguing that he was only acting, that the love he bears for Posthumus was the reason why he had put Imogen’s faith to the test. Greatly relieved, Imogen regrets that Jachimo will be leaving tomorrow. She gladly agrees to look after his trunk of valuables which he makes a point of asking her to look after for the night.