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.
Michel Carré
He went to Paris in 1840 intending to become a painter but took up writing instead. He wrote verse and plays before turning to writing libretti. He wrote the text for Charles Gounod's "Mireille" (1864) on his own, and collaborated with Eugène Cormon on Bizet's "Les pêcheurs de perles". However, the majority of his libretti were completed in tandem with Jules Barbier, with whom he wrote the libretti for numerous operas, including Camille Saint-Saëns's "Le timbre d'argent" (libretto written in 1864, first performed in 1877), Gounod's "Faust" (1859), "Roméo et Juliette" (1867), and Offenbach's "Les contes d'Hoffmann" (1881). As with the other libretti by Barbier and himself, these were adaptations of existing literary masterworks.