Bosola and Antonio serve as foils for each other. They are on opposing sides of the central conflict, but there are important similarities in their upbringing and social position. Antonio initially becomes an employee of the Duchess out of a desire for wealth and power. He eventually gains access to both when he and the Duchess secretly marry. His initial desire to enjoy the aristocratic world of the Duchess and her brothers is one of the things that binds him to Bosola. At the beginning of the play, Bosola is presented as a character with a dark past whose sole desire is stability and upward mobility. He becomes the Cardinal’s employee against his better judgment because he is desperate to change his life. Bosola and Antonio are similar, therefore, because they are both outsiders—men born without wealth and luxury who are each, in their own way, attempting to access it through the same aristocratic family.
The men are also paralleled by their death. Bosola mistakenly attacks and kills Antonio: because it is dark, Bosola thinks that Antonio is the Cardinal. This is an especially painful moment for Bosola, because he has sworn to protect Antonio from the wrath of his in-laws. However, only a short time after killing Antonio, Bosola also dies accidentally—Ferdinand stabs him during an attempt to attack the Cardinal. Therefore, both men are attacked accidentally by a man aiming to kill the Cardinal instead. The unfortunate circumstances that link their downfall is a part of their shared background. Neither man ever manages to feel secure and at home in their inherited world, and they die in confusion and darkness. Where their ambition once led them together, the violence and corruption of the aristocratic class now leads them to a parallel end.
The Duchess and Julia serve as foils in the play; they are the two central female characters, and their agency and sexuality is policed by the men around them. The treatment of these two women by the men around them reveals important aspects of how all of the characters think about power and sexuality. Most of the play’s conflict takes place over the Duchess, as her brothers attempt to control her, prevent her from remarrying, and ultimately destroy her life. The Duchess’s sexual behavior is therefore severely policed; she is ostracized for secretly marrying Antonio and having children with him. Julia, on the other hand, is cheating on her husband with the Cardinal. Initially, this makes it seem as though she has a degree of sexual freedom that allows her to enjoy sex outside of her marriage. However, she is consistently berated by the Cardinal for her lack of morality. Despite their different circumstances, these two women are ultimately most similar in how they are murdered.
After her brothers discover her secret marriage and children, the Duchess is deceived and ultimately killed. Because she believes that her family is already dead, the Duchess welcomes death. Only a few scenes later, in Act 5, Scene 2, after having to dissuade her from investigating his corruption and misdeeds, the Cardinal forces Julia to kiss a poisoned bible, and she dies instantly. Their tragic deaths are paralleled for multiple reasons. Ultimately, they are both killed to preserve wealth and corruption, and their deaths are a result of their refusal to adhere to the strict patriarchal world imposed upon them. They die at the hands of Ferdinand and the Cardinal, who come to represent the force of corruption and wealth that keep them from acting freely.
