By 1964 Callas had all but retired from musical life. In 1961 she recorded her first disc of French arias, sang in performances of Medea at Epidaurus in Greece and at La Scala and made a single concert appearance in London. In 1962, she did even less; a short concert tour, taking in London and cities in Germany, plus a couple of arias for a BBC TV appearance. 1963 saw more concerts in Berlin, Dusseldorf, Stuttgart, London, Copenhagen and Paris, plus more recording sessions of French arias at the beginning of the year. At the end of the year and at the beginning of 1964 she embarked on more intensive recording activity, possibly in preparation for her upcoming return to the operatic stage in Tosca and Norma. Three discs were issued in 1964, one of classical arias by Mozart, Beethoven and Weber, one of arias by Rossini and Donizetti, and one of Verdi arias, with more of the Verdi sessions being released in 1972, shortly after she emerged from self-imposed exile to teach a series of masterclasses at the Juilliard School in New York. Though more of these sessions, plus some made in 1969, were eventually released after her death, these were the only ones she agreed to.

Though all three of the discs issued in 1964 revealed some pronounced vocal problems, the Verdi disc is by far the most successful. She seems less preoccupied with her vocal problems, more engaged with the material and consequently the singing has a freedom that is lacking in the other two discs, though this does mean we also get quite a few squally notes above the stave.

Desdemona’s Willow Song and Ave Maria might be considered an uncharacteristic piece for Callas, but she is alive to every shift of mood. As it rarely strays above the stave it also presents her with the least problems vocally. It is a great pity EMI didn’t think to employ someone to sing Emilia’s lines, but Callas skillfully uses a different tone for the comments to Emilia from the one she uses for Barbara’s song. Throughout one feels Desdemona’s anxiety, which erupts with a sudden passionate outburst when she bids Emilia goodbye. The Ave Maria profits from her deep legato, the final Ab spun out in the best tradition.

Both of the Aroldo arias are thrilling, especially Mina’s Act III solo, a superb piece which Callas fills with drama and significance, bringing the cabaletta to a rousing conclusion.

Elisabetta’s Non pianger mia compagna from Don Carlo doesn’t really come off. Though her legato is still excellent, she sounds strained here and she can’t float the climactic phrases as she should. Eboli’s O don fatale, though, is another matter entirely. The whole aria brims with contrast and drama, and one registers each change of expression. She vehemently launches into the opening section, spitting out the words ti maledico, but then moulds rather than sings the o mia regina section, her legato line superb, her rich lower register digging deep into its melancholy. Finally as she realises she still has time to save Carlo, she brings the aria to an ecstatic close. OK, so there are a couple of off centre high notes, but they fade into insignifance next to the thrilling commitment of the singing.

When I reviewed all three of these 1963 recitals here back in January 2017, I mentioned that my wobble tolerance could vary from listen to listen. Sometimes I find the acidulous tone and stridency hard to take; on others I barely notice them as I get wrapped up in the musical imagination. It’s safe to say that on this occasion the latter reaction was in play.