Could there have been a touch of Brendel-inspired whimsy about the idea of a concert marking the 222nd anniversary of Mozart’s birth? Whoever came up with the jest, it was that triple two which provided the cue for this gala evening in Strasbourg in 1978 in aid of the Musicians’ International Mutual Aid Fund. The concert was released on a pair of Philips LPs in November 1978. The performance of the C major Piano Concerto would later be incorporated into Brendel’s complete cycle of the Mozart keyboard concertos but this is the first time this well-recorded event has appeared on CD.

The programme was Idomeneo-themed. It was rare for Mozart to reconfigure major works but in Vienna in March 1786, seven weeks before the premiere of Le nozze di Figaro, he oversaw a semi-professional revival of Idomeneo, for which he made significant alterations and provided additional music. This included a recitative and aria, probably intended for the start of Act 3, in which Ilia suspects Idamante of infidelity.

That addition itself inspired a new composition in December 1786, when a more or less identical text was used by Mozart to create his concert aria ‘Ch’io mi scordi di te’, a glorious piece for soprano, winds, strings and piano obbligato. The fact that Mozart wrote the piece for the 21-year-old Nancy Storace, his first Susanna in Figaro, with himself as pianist, has inevitably led to speculation that it was a private love-duet in concert form.

The C major Concerto, which sports an echo of Idomeneo in its finale, also had its premiere in December 1786, as did the Prague Symphony. This was originally intended to be part of the Strasbourg programme but ‘had to be changed’, producer Erik Smith mysteriously records. This is a pity. The substituted work, Mozart’s late G minor Symphony heard in a performance that is nicely groomed but never especially remarkable, becomes a bit of a red herring.

The concert’s opening sequence works beautifully, as we move seamlessly from the Idomeneo Overture, through the superb recitative which begins the newly added 1786 scena, to the lovely aria with violin obbligato ‘Non temer, amato bene’. With Jessye Norman somewhere near her vocal and theatrical best, and lovely solo playing from Hugh Maguire, Marriner’s former colleague and leader at the LSO, this is well worth disinterring.

In the Nancy Storace concert aria, alas, Norman seems chilly and uncertain, picking her way through the notes in a way that rather subverts the idea that this is Mozart at his emotionally, not to say erotically charged best. Here Mozart’s admirers, and Brendel’s, would be better advised to seek out the wonderful recording Brendel made 10 years earlier with Elisabeth Schwarzkopf accompanied by Szell and the LSO (EMI, 3/70).

The merits of the fine performance of the C major Concerto, with which the concert ends, are well known. Had this been a studio recording, I suspect that the first page or two after the piano’s initial entry might have been remade, when the players had ‘warmed up’, so to speak. But the wonder of live music-making is that it has its own trajectories and agendas, as here in a performance that grows in stature and goes on growing. The slow movement is especially memorable, profoundly felt. It is also ornamented, where required, in a way that strikes a perfect balance between austerity and elaboration.