We recall that Fidelio was first given as Leonore – in Vienna in November 1805, in three acts – before an uncomprehending audience of invading Napoleonic troops. Acts 2 and 3 corresponded to the first part of Fidelio’s Act 1 (although in a different order and with two extra numbers) and to Fidelio’s Act 2, albeit with many differences in the grand final scene, the ‘public’ part. Leonore’s Act 2 began with a different version of Pizarro’s entrance march, included a (later cut) duet with obbligato instruments for Marzelline and Leonore then continued to the end of Fidelio’s Act 1. But there was a wholly different curtain: in 1805 the prisoners are dismissed to their cells earlier without singing, and Pizarro and the chorus finish the act with another bloodthirsty march finale.

Leonore in 1805 was very number-orientated. Act 1 began with Marzelline’s aria, then came her duet with Jacquino, then a trio with Rocco (soon cut), then the famous quartet. Each of the work’s three acts was centred by Beethoven around one style and one character: Act 1: Singspiel Marzelline; Act 2: Melodrama Leonore; Act 3: Tragic Florestan. In keeping with his normal practice, René Jacobs’s new performance does not present a carbon copy of the original work as it survives but seeks a structure dramatically self-explanatory for our time. This is done with knowledge, taste and skill, far removed from crude modernising. After checking the 1806 and 1814 further versions of the score, Jacobs presents here a slight augmentation of the dialogue, especially around Marzelline in Act 1. Also she is given ‘Zärtliche Liebe’, a 1795 Beethoven song, to sing when she works in the prison, and allowed to join in with her father Rocco at the end of ‘Hat man nicht auch Gold beineben’ (this aria is now regularly taken into Fidelio performances we hear today). She is also given a dialogue from the 1806 version which allows her to make up with Jaquino after Leonore is revealed to be a woman.

Jacobs writes a passionate note in the CD booklet championing 1805 as the best version of the opera. He then backs it up with a swift, dramatic musical performance. As in the past, the result often sounds like a young Klemperer with original instruments, never afraid to let wind, brass or drums speak their parts out as contributors to Beethoven’s dramatic timbre. If you find his tempos distractingly swift – for examples, check the Prisoners from this Act 2 or the trio around the bread in Act 3, ‘Euch werde Lohn’ – remember that our Fidelios, with weightier modern Romantic orchestras, have tended to get slower.

It makes for a performance well prepared and cast with the lighter (but always agile) voices that Jacobs tends to favour. Johannson enjoys herself with Marzelline’s florid part – in this 1805 version she is effectively promoted to the role of co-principal with Leonore. The Act 2 duet ‘Um in der Ehe froh zu leben’ – a loss much regretted after 1805 – surely sees one of the first professional attempts by near contemporaries to borrow the effect of Mozart’s Figaro ‘Sull’aria’. Petersen is excitingly fluent in ‘Ach, brich noch nicht, du mattes Herz’, Leonore’s Cherubini-like and altogether more virtuoso aria of intent to free her husband. The men throughout are in reliably good voice, but don’t expect Heldenstimmen.

The recording – live from the Philharmonie de Paris a little over two years ago – serves both show and composer well. I find this the most convincing version of Leonore yet. It never sounds merely like a Fidelio manqué and comes highly recommended.

Of course, there does not have to be an original versus revision winner. Yet, despite Jacobs’s arguments about the 1805 version’s greater tensions (especially, he believes, the ending after the trumpet and the Minister’s arrival), it is hard to throw off the spectacles of hindsight and not find the whole Fidelio structure much tighter than the obvious operatic space-filling of Leonore’s original Act 2.