Despite temperamental singers and the obligatory backstage intrigues, Mitridate, premiered in Milan in 1770, was Mozart’s first great operatic triumph. Drawing loosely on Racine, the plot focuses on the rivalry between the king, Mitridate, and his two sons – the faithful Sifare and the devious Farnace – for the hand of Princess Aspasia; this being Enlightenment opera seria, Farnace is overcome by remorse and Sifare duly gets the girl. Virtuoso display is the order of the day, with extravagant bravura arias tailored more to the singer than the dramatic situation. But amid the conventional note-spinning there are numbers of striking beauty: Mitridate’s tender opening cavata; Farnace’s eloquent aria of remorse; the impassioned G minor Act 1 aria for Aspasia, torn between love and duty; or, most moving of all, the Gluckian ombra scene where she prepares to take poison.

Of the two previous recordings, the more theatrical, by far, is the Decca set vividly conducted by Christophe Rousset. While that remains a first choice, this live Salzburg recording offers fair value on two mid-price discs. There are wholesale cuts in the recitatives (which few will lament) and nips and tucks in the arias that will worry some more than others (my only serious regret was the loss of the minor-key central section to Farnace’s fiery “Venga, pur”). As usual, Orfeo provides a synopsis but no libretto. Norrington directs with plenty of dramatic energy, though the recording of the orchestra (modern instruments, period-style bowing and articulation) lacks ideal presence.

There are two outstanding performances. As Mitridate, Bruce Ford, at the peak of his powers, is far smoother and more sympathetic than Rousset’s Giuseppe Sabbatini in the beautiful opening number, and, unlike Sabbatini, conveys fury without coarsening his tone. Christiane Oelze makes a less impassioned Sifare than Bartoli on the Rousset recording. But her sweet, unblemished tone, crystal-clear coloratura and unfailingly elegant sense of phrase give consistent pleasure.

As Aspasia, Cyndia Sieden is exciting in the stratosphere, though lower down – most crucially in the ombra scene – her tone lacks body and colour, even more so by comparison with the magnificent Natalie Dessay for Rousset. Vesselina Kasarova, long a Salzburg favourite, evidently went down well with the Kleines Festspielhaus audience. But the alto castrato role of Farnace, impressively taken on the rival set by countertenor Brian Asawa, lies way too low for her, prompting some forced, ugly tone and grotesque-sounding plunges into a baritonal chest register. I’m glad to have heard this Salzburg performance, above all for Ford and Oelze. Most Mozart lovers, though, will find the stunningly cast Decca recording worth the extra investment.