chunk: After enjoying the favours of Onaelia, niece to the duke of Medina, the Spanish king repudiates her and her son, Sebastian, making Paulina, daughter of the duke of Florence, his queen. On hearing this, the noble soldier Balthazar works on the conscience of the king to take back Onaelia. Despite the threat of civil war, the king refuses. Count Malatesta proposes to the queen that she pretend to be pregnant, to sound the hearts of the Spanish people. Roderigo, Lopez, and Valasco, dons of Spain, rally to the cause of their majesties against the duke of Medina's faction. Angered at her rival, the queen proposes to Balthazar the murder of Onaelia and her son, to which he pretends to acquiesce after receiving the king's command. But, loyal to Onaelia, Balthazar announces these plots to Medina, who disguises himself as a French doctor to gain access to the king.