Masks fall. They don’t dissolve, or dissipate. Masks fall, they drop, they plunge into space, into nothingness – sometimes with urgent swiftness, sometimes with infinitesimal, agonising slowness. What is left behind is often described as ‘naked’ truth or ‘stark’ reality: unadorned, uncompromising, fixed. Things are as they are, not as we might wish them to be.

Giuseppe Verdi’s operas were designed around this very principle. The conventions of 19th-century melodrama required a building of tension towards a final scene of revelation, when the protagonists at last see each other in their true light. In Un ballo in maschera (1859), the masked ball of the title is just such a denouement: a ruler is revealed as a penitent libertine, a respectable wife is implicated in adultery, a close friend is an assassin and traitor. But the whole opera is a series of unmaskings, all steps towards this ultimate, irrevocable disclosure.

Impatience with disguise – at least, with social hypocrisy – was also part of Verdi’s nature. Writing to a friend, Cesare De Sanctis, in Naples in 1854, Verdi anticipated a lack of success for La traviata in that city, because ‘your priests and monks would be afraid to see on stage certain things that they do very well in obscurity – and that it would be much better to do in the light of the sun in the public piazza in the manner of Diogenes’. A similar issue would arise again a few years later with Un ballo in maschera. Indeed, if thematically the opera was all about unmasking, its own history described precisely the reverse process. The original source, Eugène Scribe’s Gustave III, ou Le Bal masqué (1833) – based on the real-life assassination of a Swedish king in 1792 – would gradually be obscured under other identities.

It all began with Verdi’s acceptance of a commission from the Teatro San Carlo in Naples in April 1856: a theatre for whom he had previously composed Alzira (1845) and Luisa Miller (1849). Verdi initially offered a setting of Shakespeare’s King Lear, on which he had been working with the poet Antonio Somma. But the theatre could not (or would not) secure one of the only three singers Verdi believed capable of playing the role of Cordelia: Virginia Boccabadati, Maria Spezia, or Marietta Piccolomini. With time running out, Verdi searched frantically for a different subject, and finally alighted on Scribe’s drama.

It was an odd choice – at least, for a composer who favoured innovation. Scribe’s play had already been set by Daniel Auber in 1833; later adaptations included those by Vincenzo Gabussi and Gaetano Rossi (Clemenza di Valois, Venice, 1841), and Saverio Mercadante and Salvadore Cammarano (Il reggente, Turin, 1843). As Somma would remark in 1858, the drama would have been accepted without difficulty in ‘Florence, Genoa, Trieste, Milan’. But not, it seems, Naples. The censors there demanded so many changes that Verdi withdrew the score and took it instead to the Teatro Apollo in Rome. There, it had its first, much acclaimed performance on 17 February 1859. Even so, the Roman censors ensured that the opera appeared in very different guise to the source material.

Censorship was itself an act of masking: a means of concealing any action or opinion that might disrupt political, religious or moral authority. With Un ballo in maschera, both the Neapolitan and Roman censors wanted the opera removed from contemporary time or close location, so that the plot’s vicissitudes could be suitably distanced from their own communities. For Naples, Verdi and Somma dutifully retitled the work Una vendetta in domino, moved the action to 17th-century Pomerania, and ensured that the king (now demoted to a duke) was murdered with a dagger instead of the ‘pistolet’ of the original play. For Rome, the opera became Un ballo in maschera and was set in Boston in North America at the end of the 1600s.

Did censors really believe that audiences were incapable of making connections between their own lives and what happened in a fictitious world a long, long way away? That spectators were as naive as, say, Fiordiligi and Dorabella in Mozart’s Così fan tutte, where a mere change of costume prevents them from recognising their lovers? In any event, few spectators, even in Italy’s turbulent 1850s, would have had experience of conspiring for a political assassination. Adultery was a different matter.

It was, Paolo Mantegazza wrote in 1873, ‘the most common and venial sin we know’, yet subject to harsh penalties under the law. More, he argued, infidelity had been institutionalised by the practice of arranged marriages, which were a form of prostitution: many of the judiciary ‘sell their daughter to a rich husband who cannot love her, who will never love her, and who will drag her down to the irresistible necessity of adultery’. And there was the double standard of how adultery was punished: women could be imprisoned for up to two years, while men faced no such sanctions (at least until 1899, and then only under certain circumstances such as introducing their mistress into the family home). Most pernicious of all, men who killed their erring wives received a much lesser punishment than for other acts of homicide.

The opera’s heroine, Amelia, is therefore deeply imperilled by Gustavo’s love – even more, by hers for him. The Neapolitan censors sought to obscure the situation by transforming Amelia into Anckarström’s sister, rather than his wife, and pointedly removed her acknowledgement of her feelings for Gustavo. Verdi was incensed:

‘For pity’s sake! If the words “I love you” don’t escape from Amelia, the whole piece remains without life, without passion, without warmth, without that enthusiasm and abandon that are necessary in scenes of this kind: if these words are taken away, the lines that follow become meaningless, and the duet no longer has any reason for being.’

Indeed, Amelia’s reluctant admission is one of the most significant revelations of the opera. Of all the unhappily married wives in Verdi’s operas (Lida in La battaglia di Legnano, Lina in Stiffelio, Elisabeth in Don Carlos), Amelia’s willingness to own her emotions, even though she rejects their physical consummation, has a striking resonance. Yet a few hours later, facing imminent death at the hands of her enraged husband, Amelia reveals that perhaps the greatest love of her life, the one she thinks of in her last moments, is her infant son. If her earlier surrender to Gustavo embodies sensual passion, the sparse lines of ‘Morrò, ma prima in grazia’ as she pleads to see her child etch her pain into the musical fabric. Motherhood saves the guilty Amelia from the fate Otello inflicts on the innocent Desdemona. Seeing his wife not as another man’s mistress but as the mother of his own son, Anckarström relents. Besides, he reasons, there is another outlet for his vengeance.

Before the fateful masked ball, Gustavo had decided that ‘duty and honour’ must separate him from Amelia by arranging a new posting for Anckarström and his wife abroad. Amid the ensuing festivities, however, Anckarström’s swift, remorseless blade severs that last attempt to hide illicit love behind social convention. Not just a mask, but a body falls. What is left is the most implacable reality of all – death.