Monimia (moh-NEE-mee-ah), an orphan. A ward of Acasto, she is loved by his twin sons Polydore and Castalio. She genuinely loves only Castalio. She secretly marries Castalio but is deceived into spending the night with Polydore. Filled with remorse for having deceived her husband with his brother, even though unknowingly, she finally poisons herself and dies, a victim of circumstances.
Castalio (kas-TAY-lee-oh), the overscrupulous twin son of Acasto. Minimizing his own passion for Monimia to be fair to his brother Polydore, he encourages his brother’s less scrupulous pursuit of the lady. After Castalio secretly marries Monimia, Polydore, ignorant of the marriage, tricks the bride into spending the night with him. When Castalio learns the truth of the affair and that his wife is dead by her own hand, he stabs himself and dies.
Polydore (PAW-lee-dohr), Acasto’s less scrupulous twin son. Ignorant of his brother’s secret marriage to Monimia, he tricks her into spending the night with him. When he learns that he has deceived his brother’s wife, he is filled with such horror and remorse that he contrives to die by Castalio’s sword.
Acasto (ah-KAS-toh), a nobleman, the father of Castalio and Polydore, and Monimia’s guardian.
Chamont (SHAY-mont), a young soldier, the impetuous brother of Monimia.
Serina (seh-REE-nah), Acasto’s daughter.