La Clemenza di Tito by Wolfgang Amadeus Mozart

Set in Rome during the reign of the Emperor Titus, this is one of Mozart’s last operas, with many twists and turns in the plot.

Vitellia greatly resents Titus, as his father took the throne from her father. Her plan to regain Imperial power through marrying Titus comes to nothing as he chooses Berenice, a princess of Judaea as his bride. So Vitellia asks her young admirer, Sextus, to assassinate Titus. Despite the two men’s friendship, Sextus will do anything for her and agrees to do whatever Vitellia asks of him. When the people of Rome demand a Roman Empress, Vitellia thinks she might be Empress after all and delays her plot, but Titus then opts for Sextus’ sister, Servilia as his wife. She, though, wishes to marry someone else, and Titus, a compassionate man at heart, agrees. This puts Vitellia in the running again but she only finds this out when it is too late to stop the murder plot. Sextus stabs Titus as the Capitol burns.

It turns out, however, that Sextus did not kill Titus. Sextus confesses his role in the plot (without implicating Vitellia) and is condemned to death by Titus, who is shocked by this betrayal of friendship. On reflection, though, Titus concludes he can only reign as a merciful ruler and plans to pardon Sextus. Vitellia cannot bear to see Sextus die for her so confesses her role as instigator of the plan to kill Titus. Although shaken by this further act of treason, the Emperor extends his mercy to Vitellia as well, and is praised by his people for his great clemency.