Un ballo in maschera (A Masked Ball) is an 1859 opera in three acts by Giuseppe Verdi. The text, by Antonio Somma, was based on Eugène Scribe's libretto for Daniel Auber's 1833 five act opera, Gustave III, ou Le bal masqué.

The plot concerns the assassination in 1792 of King Gustav III of Sweden who was shot, as the result of a political conspiracy, while attending a masked ball, dying of his wounds thirteen days later.

It was to take over two years between the commission from Naples, planned for a production there, and its premiere performance at the Teatro Apollo in Rome on 17 February 1859. In becoming the Un ballo in maschera which we know today, Verdi's opera (and his libretto) underwent a significant series of transformations and title changes, caused by a combination of censorship regulations in both Naples and Rome, as well as by the political situation in France in January 1858. Based on the Scribe libretto and begun as Gustavo III set in Stockholm, it became Una vendetta in domino set in Stettin, and finally Un ballo in maschera set in Boston during the colonial era. It became one of the most frustrating experiences of Verdi's career.

From the mid-20th century, it has become more common for the setting to revert to its original 18th-century Stockholm location. A re-creation of the original Gustavo III has been staged in Sweden.

Composition history
For a full account of the evolution of the opera which eventually became Un ballo in maschera, see Gustavo III (Verdi)
1857: From Gustavo III to Una vendetta in domino
A commission by the Teatro San Carlo in Naples in early 1857 led Verdi to begin to oversee the finalization of the libretto (also by Somma) for Re Lear with the aim of presenting the finished opera during the 1858 carnival season. When this proved to be impracticable, Verdi turned to the subject of King Gustav III's assassination as portrayed in Scribe and Auber's opera, albeit not an historically accurate narrative. That subject was well known and had been used by other composers, including Saverio Mercadante for his Il reggente in 1843.

For the libretto, Scribe retained the names of some of the historical figures involved (including fortune teller Ulrica Arfvidsson, the conspiracy, and the killing at the masked ball, but, as noted by Budden, "it was a simple case of 'cherchez la femme'": for the rest of the play Scribe invented the romance between the King and the fictional Amélie the wife of the king's secretary and best friend, and adds characters and situations such as Oscar, the page boy.

Somma's new libretto, known as Gustavo III, was presented to the censors in Naples by late 1857. By November, Verdi informed Somma that objections had been raised and revisions demanded by the censors, the most significant of which was the refusal to allow the depiction of a monarch on the stage - and especially the monarch's murder. As had happened with Rigoletto, changes in characters' names and titles were proposed (the King of Sweden became the Duke of Pomerania; Anckarström became Count Renato) and the location was moved from Stockholm to Stettin.

Working together with Somma over Christmas, Verdi accommodated these changes. Somma was asked to change the names of the characters on the Gustave libretto while Verdi worked on completing sketches of the music. The name of the opera became Una vendetta in domino.

By 9 January 1858, prior to setting out for Naples, Verdi wrote from his home the San Carlo that "the opera is done and even here I am working on the full score". The composer then travelled to Naples and rehearsals of Una vendetta were about to begin when, on 14 January 1858, three Italians attempted to assassinate Emperor Napoleon III in Paris, an event which was to affect the opera's production.

1858: The censor blocks Una vendetta
The imposition of still further, more stringent requirements by the censor incurred Verdi's wrath. He broke his contract, returned to Sant'Agata in April, and was sued by the management of the San Carlo house. This provoked him to lodge a counter-claim against the theatre for damages and, eventually, the legal fight ended.

It was during this period of turmoil that Verdi was to describe the previous sixteen years of his composing life: in a letter to Countess Clara Maffei, he states: "From Nabucco, you may say, I have never had one hour of peace. Sixteen years in the galleys!"

1859: Una vendetta becomes Un ballo in maschera
When the legal issues were resolved within a few months, Verdi was free to present the libretto and musical outline of Gustave III (which was basically Una vendetta with characters' names and locations changed) to the Rome Opera. There, the censors demanded further changes. Removing the action from Europe, the location became Boston during the British colonial period and the leading character became Riccardo, the Count (or Earl) of Warwick. At this point, the opera became Un ballo in maschera set in North America.

Performance history

Notable productions
Un ballo in maschera received its premiere performance at the Teatro Apollo in Rome on 17 February 1859 and was immediately successful. The opera was first seen in New York its US premiere on 11 February 1861 and in the UK on 15 June of that year.

In the 20th century, especially after a 1935 production in Copenhagen, many modern stagings have restored the original Swedish setting and characters' names. On 7 January 1955, Marian Anderson, singing the role of Ulrica, broke the "color barrier" at the Metropolitan Opera, becoming the first African-American vocal soloist to appear with that company.

A "hypothetical reconstruction" of Gustavo III, based on the unorchestrated original and much of Una vendetta "grafted" onto Un ballo's score, occurred in a production by the Gothenburg Opera in Gothenburg, Sweden in 2002.

The opera has become a staple of the repertoire and is now performed frequently.

Homosexuality of Gustav III
Scribe's libretto for Gustave III includes details that could be understood as signs of the king's homosexuality. Verdi and Somma eliminated many of these coded signals, but new codes take their place, particularly relating to the character of Oscar. David Richards has argued that although the opera was no longer explicitly based on Gustav III, Verdi deliberately deviated from his usual practice and set Oscar for a soprano - despite disliking women singing men's parts: "Verdi goes as far as one could go within the repressive conventions of his period to portray Gustavo (based on a widely known flamboyantly homosexual ruler) as either a gay man or, at a minimum, a bisexual man". Richards believes this therefore demonstrates that "Verdi’s art embraces all forms of sexualities". Ralph Hexter has examined the “masking” of homosexual aspects of the main character and how it relates to the idea of masking in the opera as a whole.

Several productions have attempted to draw out this suggestion - most notably the staging by Göran Gentele for the Royal Swedish Opera in 1959 where Gustavo is having an affair with his Oscar, even while pining for Amelia and also the 1993 staging by Götz Friedrich for Berlin.

Influence of French opera is felt in the first scene, both in the vocal writing for Oscar the page-boy, sprinkled with coloratura effects, and in the closing ensemble in which Riccardo invites everyone to visit the witch's den in disguise. The music of this ensemble combines French-style elan and a sense of joie de vivre with continued low grumblings from those plotting Riccardo's assassination.