The play is set in ancient Greece. The city-state of Corinth is ruled by a Queen (otherwise unnamed), a middle-aged widow with an adult son, Theander. The Queen is a virtuous, just, and capable ruler, but Theander is "a vicious Prince," and the play's villain. For some time before the play's action starts, Theander has been the intended husband of Merione, a young ward of the Queen who has grown to adulthood in her court. This situation changes at the start of the play: Corinth's military conflict with Argos has been resolved peacefully, and the Argosian ruler Agenor has come to Corinth with the Queen's general Leonidas to formalize the peace. The Queen decides to promote a dynastic marriage between Agenor and Merione. Theander is unhappy at losing his intended bride.