Acknowledging that Escalus may have a more thorough knowledge of state affairs than even the Duke himself, Vincentio (the Duke) puts Escalus in charge of carrying out his commission which is to deputize Angelo as the head of state, giving Angelo full authority to act on his discretion, during Vincentio’s absence from the city. When Angelo is summoned and told of his deputation, Angelo objects, citing his inexperience. Citing Angelo’s virtues, the Duke justifies his decision. Angelo is told that Escalus will be his second in command. Subsequently, the Duke departs, justifying his departure’s hurry and lack of ceremony to the circumstances which require them.
Lucio and two gentlemen are sharing their thoughts about this and that, including the unpleasantness that would result if the various Dukes, including their own Vincentio, were to fail coming to terms with the King of Hungary when they are joined by Mistress Overdone who tells them about Signior Claudio’s arrest. Apparently, Signior Claudio has gotten the unwed Madam Julietta pregnant for which he will pay with his life in three days. Intrigued, Lucio and the gentlemen go to verify the extraordinary news, while Mistress Overdone is joined by Pompey, her servant, who informs her that by state proclamation all brothels in the suburbs of Vienna will be shut down. He adds, however, that city brothels, thanks to the clout of a particularly influential city official, will remain operational. Subsequently, Mistress Overdone is distressed as her livelihood--prostitution--though technically illegal has never run afoul of the law until now. Presently, Claudio is spotted in the Provost’s custody, complaining about the unnecessity of parading his arrest for all to see. The Provost argues that he is only doing what he has been ordered to do. At this point, Lucio manages to get a word in with Claudio who confirms the reason for his arrest and his death sentence. Lucio advises Claudio to appeal to Vincentio. Claudio says that he would but for Vincentio’s mysterious absence. Claudio gets an idea: He tells Lucio to get in contact with his sister, who is in the process of becoming a nun and who in Claudio’s words has an uncanny ability to reason and persuade, and to convince her to plead Claudio’s case directly to Angelo. Lucio agrees to do so.
Having applied to Friar Thomas to be provided with a friar’s robe, Vincentio explains the rationale behind the request.
Leniency with regards the enforcement of Vienna’s harsh laws have rendered those harsh laws irrelevant. To suddenly enforce them now, however, would worsen the situation as doing so would undermine the Duke’s credibility. Consequently, Vicentio has delegated his authority to Angelo, a man whose virtues are reputed to be such that if he were to enforce Vienna’s harsh laws that it would seem only natural.
What Vincentio would like to know is if Angelo’s reputed virtues will justify the application and enforcement of those harsh laws or if Angelo’s reputed virtues will prove to be, like the harsh laws themselves, ideal in the abstract but impractical and therefore irrelevant to everyday use. And the only way that Vincentio can do this is to freely circulate through Vienna incognito, hence the request for the friar’s robe.
Isabel, a novice (a nun in training), is complaining to Francisca, a nun, about the laxness of the restraints put upon a nun when a man’s voice is heard at the front gate. Francisca prompts Isabel to answer the call as Isabel is yet a novice and is therefore at liberty both to talk and to show her face to men.
The man at the gate is Lucio who says that he’s come to speak with Isabel about her brother’s current unhappy predicament. Isabel identifies herself, and Lucio relates unto her Claudio’s situation, of how he has gotten Juliet pregnant though she is unwed, of how Lord Angelo has taken it upon himself to enforce Vienna’s impossibly harsh laws which has condemned Claudio to death, and of how the Duke’s mysterious absence has left Claudio’s only option for appeal in the hands of Isabel. Isabel doubts she can make a difference, but upon Lucio’s urging, she agrees to undertake the task of personally appealing Lord Angelo for her brother’s life.