In the play, two different groups of brothers—Vindice and Hippolito, and the various squabbling sons of the Duke—serve as foils to each other, exhibiting very different attitudes towards brotherhood. While Vindice and Hippolitio work together closely in pursuit of their mutual goals, the Duke’s sons work to undermine and sabotage each other. This gulf is emphasized when Lussurioso is arrested on the orders of his father and his step-brothers quickly devise a plan to expedite his execution. Though the step-brothers cooperate briefly in order to remove their eldest brother, who stands to inherit the Dukedom, they quickly devolve to further infighting:
Ambitioso. Excellent. Then am I heir – duke in a minute!
Supervacuo. [Aside] Nay, And he were once puffed out, here is a pin
Should quickly prick your bladder.Ambitioso. Blest occasion!
He being packed, we’ll have some trick and wile
To wind our younger brother out of prison,
That lies in for the rape. The lady’s dead,
And people’s thoughts will soon be buried.Supervacuo. We may with safety do’t, and live and feed:
The duchess’ sons are too proud to bleed.
Ambitioso, whose name indicates his ambitious nature, celebrates his older brother’s apparent execution as he believes he will now assume his place on the throne. In a private aside, however, Supervacuo, whose name reflects a vacuous or “insubstantial” personality, plans to supplant Ambitioso by violent means once he is “puffed out”—or, in other words, once his ego has been inflated by the anticipation of greater power. In contrast, Vindice and Hippolito exhibit none of the competition, violence, and untrustworthiness that mars the relationship between the Duke’s sons. Their unbreakable trust and mutual cooperation are emphasized through comparison to the royal brothers’ constant infighting.
