There is no shortage of rare Donizetti operas set in exotic locations – Emilia di LiverpoolZoraida di GranataHarrison di Accrington (okay, artistic license exercised on that final one) – so a religious drama set in Armenia during the Roman occupation might seem nothing new. In fact, Les Martyrs may be more familiar than it first seems, for it is largely a French rewrite of Poliuto, composed for Paris in umbrage after the latter failed to get the backing of the Neapolitan censor in 1838 and was pulled at the last minute. Adolphe Nourrit, for whom the original role of Poliuto was composed and whose career was on the wane, felt betrayed by the opera’s cancellation and committed suicide the following year.

Donizetti, under commission to produce his first opera for Paris, resolved to revise Poliuto and a French text was written by Eugene Scribe, conforming to the conventions of French Grand Opéra, but which retained much of the original music from Naples. Poliuto is rarely staged. It opened the 1960 La Scala season (there’s a famous live recording) and it does the same at Glyndebourne next summer. Les Martyrs is excavated with even less frequency, but operatic archaeology is what Opera Rara was created for. Employing a new critical edition by Flora Willson, Mark Elder led the forces of The Orchestra of the Age of Englightenment in a concert performance which demonstrates what a tremendous work it is.

While much of the music is recognisable from Poliuto, Donizetti fleshed out the characters far more, developed choral scenes and wrote new recitatives. The plot is based on Pierre Corneille’s 1642 play Polyeucte about Christian martyrdom. In the opera, Polyeucte has just converted to Christianity (outlawed by the ruling Romans). Pauline, his wife, is a tragic figure, torn between love for Polyeucte (whom she has secretly married) and her love for Sévère, her former husband, believed dead. Matters are thrown into turmoil as a new proconsul arrives – and turns out to be none other than Sévère, who’s come to Armenia to seek out Pauline. The inevitable conflict between state, religion and love ends with Pauline converting to Christianity to join Polyeucte in being flung to the lions as the curtain falls.

The role of Polyeucte/ Poliuto was conceived for Nourrit, who was one of the first tenors to employ chest register for top notes, as was Gilbert Duprez, who gave the actual première. Tenor Michael Spyres has no less remarkable a voice, with a thrilling top – even surprising the audience by pinging out a high E natural in “Oui, j'irai dans leurs temples!” – and amazing baritonal depths. It’s a long, challenging role and Spyres’ stamina to sustain it to the end was admirable.

Joyce El-Khoury was absolutely stunning in the role of Pauline, as demanding a role as Polyeucte. She has the ability to pluck pianissimi from thin air, while at full tilt, her soprano has tremendous agility and power. Her Act I aria “O toi, qui fus témoin de l'amour de Sévère” displayed these qualities in abundance.

The role of Sévère was nobly sung by David Kempster, his grainy baritone reliable rather than thrilling. His Act III duet with El-Khoury, “Ne vois-tu pas qu'hélas! mon cœur succombe et cède à sa douleur?” (Do you not see, alas! my heart succumbs and gives (her/him) pain?), was one of the evening’s many highlights. Wynne Evans was a lively Néarque, Polyeucte’s friend and fellow Christian, while to have basses of the quality of Brindley Sherratt and Clive Bayley in the roles of Félix (Pauline’s father) and Callisthènes (the high priest) was luxury casting indeed.

Donizetti has a happy knack of writing jolly orchestral music, regardless of how seriously the drama has turned. The Overture is a joyous romp for the most part, countered with delicacy in the string and harp writing and a choral interjection, along the lines of Rossini’s overture to Ermione. The Opera Rara Chorus, small in number but big in heart, was splendid in Donizetti’s many choral scenes. The woodwinds of the OAE were on superb, characterful form throughout, while the brass impressed, especially in the ‘Battle of the Gladiators’ entertainment laid on for Sévère’s arrival. Mark Elder’s meticulous preparation and enormous enthusiasm shone through, spurring his forces along to the powerful closing scene. To see the double basses, lined up along the back of the platform, furiously sawing their way through the tremendous ensemble close to Act III was a thing of joy!

Les Martyrs was far more than preparatory homework for Glyndebourne's Poliuto next summer. This performance – as so often with Opera Rara – was a happy revelation.