Eventually, it was agreed that it could be called Un ballo in maschera, the name by which it is known today, but Verdi was forced to accept that the location of the story would have to be Colonial Boston.
It was known to be a subject dear to the composer,[2] but this libretto, for which Somma and Verdi had worked for some time, raised concerns for Verdi, not the least of which was finding a suitable cast in Naples, given the practice of a company engaging a group of singers for an entire season and giving them the major roles to sing in all productions, thus forcing a composer to take into account their strengths and weaknesses in the roles he was creating.
Finally, in a letter which he wrote to Torelli in September 1857, Verdi confessed that he had "looked through an infinite number of plays.....but not one of them will do for me..."[4] but he then described an existing libretto which interested him, one which was written by the French playwright and librettist Eugene Scribe for Daniel Auber's very successful 1833 opera, Gustave III, ou Le bal masqué: Verdi turned to the historical subject of King Gustav III of Sweden, who was shot while attending a masked ball in Stockholm in 1792 and died thirteen days later.
In his version, Scribe had retained the names of some of the historical figures involved including Gustave, Anckarström (the king's secretary and his best friend), Ulrica Arfvidsson (the fortune teller), and conspirators Ribbing and Horn; the conspiracy itself; and the killing at the masked ball.
As noted by Budden, Scribe invented much of the rest of the action, including Gustav's romance with the fictional Amélie[6] (Anckarström's wife) and he added characters and situations such as the page boy, Oscar.
"[9] While Verdi did not necessarily see a problem in changing location, he did lament the loss of other things: "what a pity to have to give up the pomp of a court like that of Gustavo III.
[12] Somma had several suggestions, including a possible new title, Il duca Ermanno[13] with a 12th Century setting, which Verdi rejected; but he did accept the proposed change to Pomerania.
Discussions with the censors eventually resulted in the location being changed to Stettin in Pomerania in Northern Germany, the main character becoming a Duke, and the title becoming Una vendetta in domino.
With the major problems seeming to have been resolved and rehearsals of Un vendetta about to begin, an attempt to assassinate Emperor Napoleon III in Paris by three Italians led by Felice Orsini occurred on 14 January 1858.
After attempting to obtain agreement on the singers during his first ten days in Naples, Verdi finally discovered that the company's management had withheld the news that the censors had refused to approve the libretto some three months before.
[26] When Jacovacci, impresario of the Teatro Apollo (where Il trovatore had been presented successfully) received the libretto, his reaction was encouraging, but he warned the composer that there may be problems with the censor.
"[27][28] At first, Verdi wanted the libretto returned, but Jacovacci's persistence prevailed, and it was found that the censors did not insist on such dramatic changes as originally had been thought possible.
The score's text required modification to agree with Ballo and not Una vendetta, orchestration was completed, and musical changes and adjustments were made.
By about 1870, after Ballo had become successful and when Italian unification removed much of regional censorship, Verdi could probably have returned the opera to its original Swedish setting,[32] but he never did so.