This might seem like yet another unfamiliar Vivaldi opera uncovered but the truth is more complicated. Giacomelli’s setting of Zeno’s libretto La Merope (derived from a tragedy by Euripedes) was performed at Venice’s Teatro S Giovanni Gristostomo during the 1734 Carnival. Four years later Vivaldi presented his own version, retitled L’oracolo in Messenia, across town at the Teatro S Angelo. This pasticcio featured music by Giacomelli, Vivaldi and probably others but only the printed libretto survives. Vivaldi was hoping to produce a revival in Vienna when he died there in 1741 and a performance took place posthumously at the Kärntnertortheater during the 1742 Carnival. Again, only the libretto survives – and it is not the same as the Venetian ‘original’ but suggests that Vivaldi revised the piece before his death. This recording presents Fabio Biondi’s reconstruction of the posthumous Viennese pasticcio, recorded appropriately enough in Vienna’s Konzerthaus.

The Sinfonia (from Griselda) typifies the vibrant élan which we have come to expect from Europa Galante: crackling fast music that packs a horn-fuelled punch surrounding a slow central movement played with a juxtaposition of delicacy and muscle. Biondi draws 10 arias from Vivaldi’s Atenaide, Catone in Utica, Motezuma, Dorilla in Tempe, Farnace and Semiramide which are readily transferrable to their new dramatic contexts. ‘Se al cader del mostro orrendo’ (from Motezuma) strikingly insinuates that the villain Polifonte is making promises he clearly has no intention of keeping (it transpires he ordered the murder of Merope’s husband and most of her children, and now wants to marry her). Thirteen numbers from Giacomelli’s La Merope include two that Vivaldi had already used in Bajazet and most are impressive evidence of Giacomelli’s qualities: the hero Epitide’s ‘Dono d’amica sorte’ shows off Vivica Genaux’s voice to full advantage; the noble Licisco’s brightly optimistic ‘Sinché il tiranno scendere’ is sung elegantly by Franziska Gottwald. We also hear the famous Farinelli showpiece ‘Son qual nave’ from Broschi’s Artaserse (sung magnificently by Julia Lezhneva’s anxious Trasimede). Licisco’s ‘Nell’orror di notte oscura’ from Hasse’s Siroe is a flamboyant highlight of the final act but the opera’s explosive dramatic climax is Ann Hallenberg’s incisive performance of Giacomelli’s intense scene for Merope when she believes her long-lost sole surviving son has just been brutally assassinated. It turns out that this zesty performance reveals a valuable examination of Giacomelli.