Un ballo in maschera (A Masked Ball) is an opera in three acts by Giuseppe Verdi with text by Antonio Somma. However, Somma's libretto was itself based on the five act libretto which playwright Eugène Scribe had written for Daniel Auber's 1833 opera, Gustave III, ou Le bal masqué. Scribe wrote about the assassination in 1792 of King Gustav III of Sweden who was killed as the result of a political conspiracy against him. He was shot while attending a masked ballroom dance and died 13 days later of his wounds.