Machiavelli's satirical play The Mandrake is, essentially, a story of desire and deception, which typically represents the Machiavellian philosophy that the end justifies the means. To understand Lucrezia’s mother’s actions, one must be familiar with the plot.

Callimaco, a young Florentine man, hears about the incomparable beauty of a woman named Lucrezia and becomes determined to bed her. Upon finding out that Lucrezia is already married and very virtuous, however, he decides to bribe a corrupt marriage broker (Ligurio), an immoral friar (Timotheo), and Lucrezia’s own mother (Sostrata) to help him convince Lucrezia to sleep with him.

Callimaco pretends to be a doctor and manages to persuade Lucrezia’s husban, Nicia, that he can cure infertility with the help of a "special potion" made from mandrake root. Callimaco also warns Nicia that the potion is very "deadly," which means that Lucrezia must sleep with another man who is not her husband, because the first man who beds her after she drinks the potion will die. Desperate to have an heir, Nicia agrees to find a man to sleep with his wife (Callimaco in disguise) and Friar Timotheo and Sostrata convince the naive and dutiful Lucrezia to agree to the plan as well.

Friar Timoteo: The end of all things; your purpose is to fill a seat in paradise, to make your husband happy. The Bible says that the daughters of Lot, believing themselves alone in the world, lay with their father, and because their intention was right, they didn't sin.

Lucrezia: What are you persuading me to do?

Sostrata: Persuade yourself, my daughter. Don't you see that a woman who has no children has no home? Her husband dies; she's left like a beast, abandoned by everyone.

Thus, Lucrezia’s mother’s position in the plan is simple⁠—she agrees because she only wishes to have grandchildren. However, we must not ignore the fact that Lucrezia’s mother indirectly convinces her daughter that murder and adultery are not sins if they justify a "greater cause," such as Lucrezia’s pregnancy.

Many would agree that Sostrata should actually protect her daughter against such cunning and evil schemes, but that is not the case in The Mandrake. Sostrata doesn't only agree to the plan but also encourages it, as she is desperate to have grandchildren and keep her social status and reputation. In the end, everyone gets what they wantCa⁠—llimaco gets to sleep with Lucrezia, Lucrezia gets a lover, Nicia will no longer be in a childless marriage, Sostrata will finally hold a grandchild in her arms, and the broker and the friar get to share some hefty prize money.