Carl Heinrich Graun owes his career to patron Frederick the Great, whose passion for music in general (and Italian opera in particular) fuelled the composer’s prolific output. But money was not the end of the king’s influence. At least three librettos, including Montezuma, have Frederick’s fingerprints on them.

Didacticism is thinly veiled in works that celebrate heroic leadership – secular morality plays with music. Silla (1753) is one such: a rollicking Roman epic in which dictator Silla spends several hours throwing his political weight about, kidnapping and threatening Ottavia (she loves senator Postumio rather than Silla), before renouncing his claim in a volte-face of a finale that ends not with spectacular military victory but the realisation that ‘Of all the victories, the greatest is the ability to triumph over one’s own heart’.

The plot may be little more than an excuse for a series of illustrative conflicts and set pieces but the music is glorious, filling out a stiff outline with a richly varied sequence of arias as well as a smattering of interesting ensembles. Frederick’s personal preference was for castratos (Carestini debuted the title-role), and the cast is top‑heavy. A lone tenor (scheming villain Crisogono) is as low as it gets. The onus lies on singers to differentiate character – particularly on disc.

This recording started life as a lavish staging by Georg Quander at Innsbruck’s Festival of Early Music in 2022. Stripped of Quander’s gorgeous visuals, music director Alessandro De Marchi (leading from the harpsichord), Coro Maghini and the festival’s own orchestra fill the gaps with crisp, brisk energy in an account that’s always on the balls of its feet, driving through the long recitatives, brass and timpani punching through in the sinfonias.

Bejun Mehta headlines a cast that includes fellow countertenors Valer Sabadus (Metello) and Hagen Matzeit (Lentulo) as well as sopranist Samuel Mariño (Postumio). Mehta leaps into the foreground with his round, muscular tone, explosively tense in vengeful opener ‘Perfido, sì comprendo’, but finding sumptuous new colour to plead his romantic case in the luscious ‘Vago adorato’ (De Marchi’s strings match him for sensuousness). His final metamorphosis arrives in the softening we hear through Act 3’s monumental closing recitative and new philosophical credo ‘Sia questo giorno’. Recitatives have to travel in an opera that pivots on a change of heart and mind, and Mehta gives us that evolution in plain sight – or sound.

Both Sabadus and Matzeit are gentler, hollower voices, and Sabadus’s lovely top notes and agility are on show in the tireless coloratura of ‘Non v’è sì barbaro’. But Mariño is a problem. The voice is thin and shrill, ‘Caro bell’idol mio’ terrifyingly wild, flung out with little control of pitch or tone. It’s unclear why soprano Eleonora Bellocci’s supple, engaging Ottavia would ever choose this whining lover. Duet ‘Barbaro traditore’ – she all stormy semiquavers against Silla’s staunch, controlled lyricism – is a highlight, as is her exquisite ‘farewell’ aria ‘In questo amplesso’. There’s stylish support from Roberta Invernizzi as Fulvia, Ottavia’s no-pushover of a mother, and tenor Mert Süngü is an exciting discovery as Crisogono, with a lovely Italianate throb and the cleanest coloratura of the cast in the demanding ‘Invan mortale’.

Can you have too much of a good thing? At nearly 200 minutes Silla tests the patience a little, and all those crucial recitatives need the impetus of the stage to really come into their own. But musically it’s excellent, a score worth coming back to – the virtuosity of Hasse or Vinci with just a hint of Handelian heart.