Co-written by Arthur Honegger and Jacques Ibert, L’Aiglon was first performed in Monte Carlo in March 1937. An adaptation of Edmond Rostand’s play of the same name, it deals with the elusive historical figure of Napoléon II – known in his lifetime as the Duke of Reichstadt and posthumously as ‘the Little Eagle’ – who, following his father’s abdication, was taken into the custody of his mother, Marie-Louise of Austria, and kept a virtual prisoner at the Habsburg court. He died, aged only 21, in 1832, but while he lived, all Europe waited, in anticipation and terror, to see if he would attempt to claim his imperial title.

Rostand’s play was written in 1900 as a travesti vehicle for Sarah Bernhardt, following her success in Hamlet the previous year, and self-consciously echoes Shakespeare in its examination of the relationship between volition and action. The Duke – drawn to Napoleonic idealism but trapped by Metternich’s sinister Realpolitik – dreams hopelessly of the France he will neither see again nor rule, though his forceful imagination gradually colours the lives of all those round him. In the climactic scene, he narrates the history of the battle of Wagram with such intensity that the old soldier Flambeau, fatally injured in a futile attempt to help the Duke escape, believes he is dying a hero’s death on the battlefield.

At the time of the opera’s premiere, the two composers kept teasingly quiet about who had written what. We now know, however, that Ibert composed Acts 1 and 5 and the Act 3 ballet, while Honegger undertook the rest. The pervasive mood is one of bittersweet nostalgia. Vocal writing and characterisation are remarkably consistent, but we can detect subtle differences elsewhere. Ibert’s contribution is characteristically refined and svelte. Honegger’s dissonances have greater bite, and his brass-writing is more elaborate and prominent. The booklet-notes make much of the opera as an expression of French nationalism in the face of the rise of Nazism, and it was indeed dropped from the repertoire during the Occupation, when Ibert’s music was proscribed. But the work is neither simplistic nor propagandist. Austrian culture was comparably under threat in 1937 and Ibert’s glorious waltzes evoke 19th-century Vienna even as they mourn its passing.

Of late there has been something of a revival of interest in the piece, with important stagings in Marseilles and Lausanne in 2004 and 2013 respectively. Decca’s recording was made in Montreal, during the series of concert performances that marked its Canadian premiere in March last year. Conducted with care and palpable affection by Kent Nagano, it boasts a fine, mostly francophone ensemble cast, with not a weak link anywhere. At its centre, in a trouser role that is a gift for a lyric soprano, is Anne-Catherine Gillet’s Duke, bright in tone and wonderfully subtle in her response to the complexities of both text and character. Marc Barrard is the touchingly funny Flambeau, while Etienne Dupuis makes Metternich all the more sinister by singing his music so beautifully. The orchestral sound is gorgeous, as is the recording itself, and only the occasional distant cough reminds us that it was made live.