[3] However, in spite of its initial short-term success and critical reaction, as represented by a review in La Gazzetta privilegiata which stated that "A new masterwork has been added to Italian music...Belisario not only pleased and delighted, but also conquered, enflamed and ravished the full auditorium",[4] in the long run, had "Donizetti poured music of the calibre of his Lucia di Lammermoor into the score of Belisario the shortcomings of its wayward plot and dramatic structure would matter less".

[5] With the success of Lucia di Lammermoor in September 1835, Donizetti moved on to stagings of Maria Stuarda, the first under that name at La Scala in late 1835.

In the case of Antonietta Vial (who was to sing the role of Irene and whom he described on first hearing her as "both a bastard soprano and a veiled contralto",[9] he was able to make adjustments to suit her vocal limitations.

By the time of the first performance, which was well received, Donizetti reported to his publisher the audience's reaction to most of the numbers, specifically that "in the duet for Vial and Salvatore, many shouts of bravi, but at the end (so they say) the situation is so moving that they were weeping".

[10] In a review of a 2011 London performance, some of the strengths of Donizetti's score are outlined: The central couple are played by bass and soprano, which brings Verdi's Macbeth immediately to mind.

[15] In July 2010, the opera was performed by the Buenos Aires Lirica[16] and a concert performance, starring Nelly Miricioiu with London's Chelsea Opera Group[17] under conductor Richard Bonynge, was given at Queen Elizabeth Hall on 13 February 2011[11][18] Belisario was given a new production at the Teatro Donizetti in Bergamo as part of the Donizetti Festival in September 2012 using the critical edition,[19] while the BBC Symphony Orchestra presented a concert performance in London on 28 October 2012 with Canadian soprano Joyce El-Khoury as Antonina and Sicilian baritone Nicola Alaimo as the title character.

Antonina hates her husband because Proclus, the slave of Belisarius, has confessed on his deathbed, that upon command of his master he had exposed her son on the shore of the ocean, thus causing his death.

Irene congratulates her father, but Antonina has already begun her work of hate, by traducing Belisarius to Justinian, and the innocent man is accused of high treason and thrown into prison on the evidence of his wife.

L'Esilio (Exile) Before the prison Alamiro and his friends lament the fate of Belisarius, whose eyes have been put out by his enemies, falsely construing and disobeying the commands of the emperor.

Irene clad as a youth arrives to act as guide to her father, who is about to be released from prison (Duet: Oh tu, che della eterna, orribil notte /"Oh thou, who in terrible darkness").