Droit du seigneur
In Mozart's "The Marriage of Figaro", which premiered in 1786 with a libretto by Lorenzo Da Ponte, the comic plot revolves around the successful efforts of the young bride and groom, Figaro and Susanna, to block the efforts of the unfaithful Count Almaviva to seduce Susanna. To achieve his aim, the frustrated Count threatens to reinstitute "droit du seigneur". It was based on a play by Pierre Beaumarchais.
Fiesque
Fiesque ("The Genoese Conspiracy") is an opera by the French composer Édouard Lalo. The libretto, by Charles Beauquier, is based on Schiller's 1784 play, "Die Verschwörung des Fiesco zu Genua", an account of the conspiracy in 1547 led by Fiesque against the ruling Doria family.