Most of Telemann’s operas for Hamburg’s Gänsemarkt theatre are lost. One of the few exceptions is Flavius Bertaridus (1729), which Sony claims is ‘absolutely a missing link in the opera repertoire’. It is based on the same story as Handel’s Rodelinda: seventh-century Lombard king Flavius Bertaridus returns home in disguise, hoping to rescue his wife Rodelinda and recover his throne from the usurper Grimoaldus. As was typical for Hamburg, the peculiar libretto presents action and arias in German but slips in about a dozen Italian arias.

It seems that Alessandro de Marchi exercised artistic licence upon Telemann’s orchestrations for a production at the Innsbruck Festival of Early Music in 2011. Moreover, some cuts, reallocations and alterations to the plot are briefly summarised in the booklet. The original Overture is lost, so an earlier French-style piece is used instead. Aside from deficiencies in the lifeless recorded sound, Accademia Montis Regalis play the Overture in a clumsily inelegant manner that hardly does Telemann any favours; the violins sound peculiarly compressed and there are intonation problems. The opening scene establishes the pattern of laboured recitatives and unevenly performed arias. Few singers emerge with much credit; nasal coloratura, ropy phrasing and over-forced singing are prevalent. The warts-and-all live recording has not served them well.

Telemann created some intriguing musical moments, such as ‘Es nehmen die Flammen’ (a florid tenor aria for Orontes, with refrains for chorus), which is followed by Rodelinda’s lullaby to her sleeping son Cunibert (‘Dormi pure, amato figlio’); it is a pity Nina Bernsteiner sings with harsh vibrato and variable tuning but she does much better with her poignant prison scene in Act 3 (‘Gemahl und Sohnes Angedenken’). Orontes has several charming love songs featuring poetic instrumental obbligatos but they are all butchered by Jürgen Sacher’s unstylish bellowing. Act 2 opens with a lovely accompanied recitative and pastoral aria replete with nightingale recorders for Flavia (Grimoaldus’s long-suffering wife), but Ann-Beth Solvang sings them stridently. Maîte Beaumont makes a better fist of the title-role: his secretive homecoming aria ‘Cari lidi’ (with fussy bassoon obbligato) is hardly on a par with Handel’s counterpart, ‘Dove sei’, but the climactic heroic trumpet aria ‘Lieto suono ti trombe guerriere’ is splendid fun. Not so much ‘a missing link’ as a glass that is only half-full.